What i have now

MixingTableBlock.java

package com.mrkelpy.miasmapothecary.blocks.MixingTable;

import com.mrkelpy.miasmapothecary.blocks.MixingTable.MixingTableBlockEntity;
import net.minecraft.MethodsReturnNonnullByDefault;
import net.minecraft.core.BlockPos;
import net.minecraft.core.Direction;
import net.minecraft.server.level.ServerPlayer;
import net.minecraft.world.InteractionHand;
import net.minecraft.world.InteractionResult;
import net.minecraft.world.entity.player.Player;
import net.minecraft.world.item.context.BlockPlaceContext;
import net.minecraft.world.level.BlockGetter;
import net.minecraft.world.level.Level;
import net.minecraft.world.level.block.Block;
import net.minecraft.world.level.block.EntityBlock;
import net.minecraft.world.level.block.HorizontalDirectionalBlock;
import net.minecraft.world.level.block.entity.BlockEntity;
import net.minecraft.world.level.block.state.BlockBehaviour;
import net.minecraft.world.level.block.state.BlockState;
import net.minecraft.world.level.block.state.StateDefinition;
import net.minecraft.world.level.block.state.properties.DirectionProperty;
import net.minecraft.world.level.material.Material;
import net.minecraft.world.level.material.MaterialColor;
import net.minecraft.world.phys.BlockHitResult;
import net.minecraft.world.phys.shapes.CollisionContext;
import net.minecraft.world.phys.shapes.VoxelShape;
import org.jetbrains.annotations.Nullable;

import javax.annotation.ParametersAreNonnullByDefault;
import java.util.Objects;

@MethodsReturnNonnullByDefault
@ParametersAreNonnullByDefault
public class MixingTableBlock extends Block implements EntityBlock {

    private static final BlockBehaviour.Properties BLOCK_PROPERTIES = buildProperties();
    private static final VoxelShape SHAPE = box(0.0D, 0.0D, 0.0D, 16.0D, 15.0D, 16.0D);
    private static final DirectionProperty FACING = HorizontalDirectionalBlock.FACING;

    public MixingTableBlock() {
        super(BLOCK_PROPERTIES);
        this.registerDefaultState(this.getStateDefinition().any().setValue(FACING, Direction.NORTH));
    }

    /**
     * Builds the properties for the current block.
     */
    private static BlockBehaviour.Properties buildProperties() {

        BlockBehaviour.Properties properties = BlockBehaviour.Properties.of(Material.STONE);
        properties.color(MaterialColor.COLOR_BROWN);
        properties.strength(2.5f, 6f);
        properties.requiresCorrectToolForDrops();

        return properties;
    }

    @Override
    public InteractionResult use(BlockState pState, Level pLevel, BlockPos pPos, Player pPlayer, InteractionHand pHand, BlockHitResult pHit) {

        if (pPlayer instanceof ServerPlayer)
            MixingTableMenu.openContainer((ServerPlayer) pPlayer, pPos);

        return InteractionResult.SUCCESS;
    }

    @SuppressWarnings("deprecation")
    @Override
    public VoxelShape getShape(BlockState pState, BlockGetter pLevel, BlockPos pPos, CollisionContext pContext) {
        return SHAPE;
    }

    @Override
    public BlockState getStateForPlacement(BlockPlaceContext pContext) {
        return Objects.requireNonNull(super.getStateForPlacement(pContext)).setValue(FACING, pContext.getHorizontalDirection().getOpposite());
    }

    @Override
    protected void createBlockStateDefinition(StateDefinition.Builder<Block, BlockState> pBuilder) {
        pBuilder.add(FACING);
    }

    @Nullable
    @Override
    public BlockEntity newBlockEntity(BlockPos pPos, BlockState pState) {
        return new MixingTableBlockEntity(pPos, pState);
    }
}

MixingTableBlockEntity.java

package com.mrkelpy.miasmapothecary.blocks.MixingTable;

import com.mrkelpy.miasmapothecary.setup.Registration;
import net.minecraft.MethodsReturnNonnullByDefault;
import net.minecraft.core.BlockPos;
import net.minecraft.world.level.block.entity.BlockEntity;
import net.minecraft.world.level.block.state.BlockState;
import net.minecraftforge.api.distmarker.OnlyIn;

import javax.annotation.ParametersAreNonnullByDefault;

@MethodsReturnNonnullByDefault
@ParametersAreNonnullByDefault
public class MixingTableBlockEntity extends BlockEntity {

    public MixingTableBlockEntity(BlockPos pos, BlockState state) {
        super(Registration.MIXING_TABLE_BLOCK_ENTITY.get(), pos, state);
    }

}

MixingTableBlockScreen.java

package com.mrkelpy.miasmapothecary.blocks.MixingTable;

public class MixingTableBlockScreen {
}

MixingTableMenu.java

package com.mrkelpy.miasmapothecary.blocks.MixingTable;

import com.mrkelpy.miasmapothecary.setup.Registration;
import net.minecraft.core.BlockPos;
import net.minecraft.server.level.ServerPlayer;
import net.minecraft.world.entity.player.Player;
import net.minecraft.world.inventory.AbstractContainerMenu;
import net.minecraft.world.inventory.ContainerLevelAccess;
import net.minecraftforge.network.NetworkHooks;

import javax.annotation.ParametersAreNonnullByDefault;

/**
 * This class implements the Menu for the MixingTableMenu. It is used to tell the server and client
 * how the inventory works in that GUI
 */
@ParametersAreNonnullByDefault
public class MixingTableMenu extends AbstractContainerMenu {

    /** The ContainerLevelAccess is just a pair of a Level and the BlockPos within the context.
     */
    private final ContainerLevelAccess CLA;

    public MixingTableMenu(int containerId, ContainerLevelAccess CLA) {
        super(Registration.MIXING_TABLE_CONTAINER.get(), containerId);
        this.CLA = CLA;
    }

    /**
     * This is an utilitary method that opens the GUI for the specified player.
     * @param player The player to the display the GUI to
     * @param blockPos The block position from where the GUI was opened from
     */
    public static void openContainer(ServerPlayer player, BlockPos blockPos) {
        NetworkHooks.openGui(player, new MixingTableMenuProvider(blockPos));
    }

    /**
     * Checks whether the player is still allowed to access the container.
     * @return boolean
     */
    @Override
    public boolean stillValid(Player pPlayer) {
        return stillValid(CLA, pPlayer, Registration.MIXING_TABLE_BLOCK.get());
    }
}

MixingTableMenuProvider.java

package com.mrkelpy.miasmapothecary.blocks.MixingTable;

import com.mrkelpy.miasmapothecary.MiasmaApothecary;
import net.minecraft.MethodsReturnNonnullByDefault;
import net.minecraft.core.BlockPos;
import net.minecraft.network.chat.Component;
import net.minecraft.network.chat.TranslatableComponent;
import net.minecraft.world.MenuProvider;
import net.minecraft.world.entity.player.Inventory;
import net.minecraft.world.entity.player.Player;
import net.minecraft.world.inventory.AbstractContainerMenu;
import net.minecraft.world.inventory.ContainerLevelAccess;
import net.minecraft.world.level.block.Block;
import org.jetbrains.annotations.Nullable;

import javax.annotation.ParametersAreNonnullByDefault;

@MethodsReturnNonnullByDefault
@ParametersAreNonnullByDefault
public class MixingTableMenuProvider implements MenuProvider {

    private final BlockPos menuBlockPos;

    public MixingTableMenuProvider(BlockPos blockPos) {
        this.menuBlockPos = blockPos;
    }

    @Override
    public Component getDisplayName() {
        return new TranslatableComponent(String.format("container.%s.mixing_table", MiasmaApothecary.MODID));
    }

    @Nullable
    @Override
    public AbstractContainerMenu createMenu(int pContainerId, Inventory pInventory, Player pPlayer) {
        return new MixingTableMenu(pContainerId, ContainerLevelAccess.create(pPlayer.getLevel(), this.menuBlockPos));
    }
}

Registration.java

package com.mrkelpy.miasmapothecary.setup;

import com.mrkelpy.miasmapothecary.MiasmaApothecary;
import com.mrkelpy.miasmapothecary.blocks.MixingTable.MixingTableBlock;
import com.mrkelpy.miasmapothecary.blocks.MixingTable.MixingTableBlockEntity;
import com.mrkelpy.miasmapothecary.blocks.MixingTable.MixingTableMenu;
import com.mrkelpy.miasmapothecary.items.MixingTableBlockItem;
import com.mrkelpy.miasmapothecary.other.CreativeTabMiasmaApothecary;
import net.minecraft.core.Registry;
import net.minecraft.world.inventory.AbstractContainerMenu;
import net.minecraft.world.inventory.ContainerLevelAccess;
import net.minecraft.world.inventory.MenuType;
import net.minecraft.world.item.CreativeModeTab;
import net.minecraft.world.item.Item;
import net.minecraft.world.item.crafting.RecipeSerializer;
import net.minecraft.world.item.crafting.RecipeType;
import net.minecraft.world.level.block.Block;
import net.minecraft.world.level.block.entity.BlockEntityType;
import net.minecraftforge.common.extensions.IForgeMenuType;
import net.minecraftforge.network.IContainerFactory;
import net.minecraftforge.registries.DeferredRegister;
import net.minecraftforge.registries.ForgeRegistries;
import net.minecraftforge.registries.RegistryObject;

/**
 * This class is responsible for registering every object into the game.
 */
public class Registration {

    /**
     * DEFERRED REGISTERS
     */
    public static final DeferredRegister<Item> ITEMS =
            DeferredRegister.create(ForgeRegistries.ITEMS, MiasmaApothecary.MODID);

    public static final DeferredRegister<Block> BLOCKS =
            DeferredRegister.create(ForgeRegistries.BLOCKS, MiasmaApothecary.MODID);

    public static final DeferredRegister<RecipeSerializer<?>> RECIPE_SERIALIZERS =
            DeferredRegister.create(ForgeRegistries.RECIPE_SERIALIZERS, MiasmaApothecary.MODID);

    public static final DeferredRegister<RecipeType<?>> RECIPE_TYPES =
            DeferredRegister.create(Registry.RECIPE_TYPE_REGISTRY, MiasmaApothecary.MODID);

    public static final DeferredRegister<BlockEntityType<?>> BLOCK_ENTITY_TYPES =
            DeferredRegister.create(Registry.BLOCK_ENTITY_TYPE_REGISTRY, MiasmaApothecary.MODID);

    public static final DeferredRegister<MenuType<?>> MENU_TYPES =
            DeferredRegister.create(Registry.MENU_REGISTRY, MiasmaApothecary.MODID);

     /**
     * This is a helper method for container registration.
     * Instead of registering the Menu itself, we register a MenuType pointing to the menu.
     * @param id The registration ID
     * @param factory The factory for the menu.
     */
    private static <T extends AbstractContainerMenu> RegistryObject<MenuType<T>> registerContainer(String id, IContainerFactory<T> factory) {
        return MENU_TYPES.register(id, () -> IForgeMenuType.create(factory));
    }

    /**
     * BLOCKS REGISTRATION
     */
    public static final RegistryObject<Block> MIXING_TABLE_BLOCK = BLOCKS.register("mixing_table_block", MixingTableBlock::new);

    /**
     * ITEMS REGISTRATION
     */
    public static final RegistryObject<Item> MIXING_TABLE = ITEMS.register("mixing_table", MixingTableBlockItem::new);

    /**
     * CREATIVE TAB REGISTRATION
     */
    public static final CreativeModeTab CustomModTab = new CreativeTabMiasmaApothecary();

    /**
     * BLOCK ENTITY TYPE REGISTRATION
     */
    public static final RegistryObject<BlockEntityType<?>> MIXING_TABLE_BLOCK_ENTITY =
            BLOCK_ENTITY_TYPES.register("mixing_table_block_entity", () -> BlockEntityType.Builder.of(MixingTableBlockEntity::new, MIXING_TABLE_BLOCK.get()).build(null));

    /**
     * MENU TYPE REGISTRATION
     */
    public static final RegistryObject<MenuType<MixingTableMenu>> MIXING_TABLE_CONTAINER =
            registerContainer("mixing_table", (id, inventory, buff) -> new MixingTableMenu(id, ContainerLevelAccess.create(inventory.player.getLevel(), buff.readBlockPos())));

}