First, I want you to type the word debug , and press enter. The cursor should move down a line, and you should see the Debug prompt, which is a simple dash. We are now in a program called Debug . Debug is a powerful utility that lets you directly access the registers and memory of your computer for various purposes. In our case, we want to enter our program into memory and run it, so we'll use Debug's a command, for assemble . Go ahead and type a100 now. The cursor will move down another line, and you will see something like 1073:0100 . This is the memory location we are going to enter assembly language instructions at. The first number is the segment, and the second number is the memory location within the segment. Your Debug program will probably pick a different segment for your program than mine did, so don't worry if it's different. Another thing to note is that Debug only understands hexadecimal numbers, which are a sort of computer shorthand. Hexadecimal numbers sometimes contain letters as well as well as digits, so if you see something like 63AF , don't worry.