This tutorial covers AMD64/Intel 64 bit programming. Instruction sets for other processors, such as ARM or RISC-V are radically different, though the concepts are the same. They all have instructions, registers, stacks, and so on. Once you know one processor's assembly language, adapting to a different processor is rather easy.
I found that I was writing code for a new processor within hours, and writing quality code within a week or two. This is going from Z80 to 6502 to 6809 to 8086 to 68000 and so on. It is interesting to be able to look at a processor's technical manuals and evaluate the power and flexibility of its instruction set.
This tutorial is aimed at novices and beginners who want to learn the first thing about assembly language programming. If you are an expert, you may or may not get a lot out of this.