We won't use debug to program in this tutorial, we'll use a real assembler. I use TASM 3.2, but MASM or any other assembler works just fine too. Now let's talk about segments. The 8086 divides it's memory into segments. Three main segments are the code, data and stack segment.
Segments overlap each other almost completely.
The first number is the segment number and the second number is the offset within the segment. As I said before, segments overlap. That means that segment begin at paragraph boundaries. Now you can start calculating REAL addresses in memory. Now we multiply the segment number with 16 and add the offset.