I wrote this tutorial back in 2010 to introduce people to x86 assembler. On a modern, 64-bit operating system this code won't run - it was designed for 16-bit systems. You can install DosBox or your favorite emulator/hypervisor like QEMU. If you go the latter route, you'll need to install an MSDOS-compatible operating system to use it. I really recommend you check out DosBox.
You'll also need the open-source Netwide Assembler (NASM) and a linker. I'm using the public domain program WarpLink for the tutorial. You can download a copy from the resources folder in this repository.
The file HELLO.ASM is a typical "Hello World" app. It introduces the basic concepts and syntax of assembly language.
The file GOODBYE.ASM is a bit more complex, taking an argument from the command line and performing conditional branching.
One day I will enhance this tutorial with more concepts, for those who really want to dabble in assembly language. I may even introduce some 32-bit gui programming, but that is for another day.