This guide will use "debug.exe", a nice app that comes after DOS 2.0 and you possibly have it on Windows folder if your running Windows OS. So, no need to download fancy assemblers or compilers.
I'll try to explain each step... but dont expect more that a text on screen...
A nice description about DEBUG.EXE can be found in...
Step 1: Undestanding DEBUG.EXE
We will be using DEBUG.EXE that was released after DOS 2.0, it's mainly used to debug 16-bits applications.
You possibly have it on Windows System folder if your running Windows OS.
In Windows XP, it can be found in C:\WINDOWS\SYSTEM32\DEBUG.EXE
Enter in command-lines (I hope you know how to do this... if not, maybe this tutorial isn't good for you), first step should be calling DEBUG.EXE, since C:\WINDOWS\SYTEM32 is included in "PATH" enviroment, you can call it any path or drive:
You can type "?" then press ENTER to see the help.
(Again) A nice description about DEBUG.EXE can be found in...