Hi Brooke,
Since you are unlikely to begin by using one of the terrain making utilities right away, we’ll figure you want to start it by hand.
Open the editor and immediately choose New, this will create the terrain folder and basic files. Remember which size map you choose so you can use the right clipboard template. When you choose the map size, it determines what you see on the in game clipboard but the terrain is actually always the same size. Quit the editor and save when it asks, this takes care of some editor house keeping.
Now create the texsrc folder inside your new terrain folder.
Find the corresponding clipboard map template file i.e. map512.bmp in the folder named “maps” in the Aheditor folder. Make a copy of the one that’s the right size and drag it to the texsrc folder you made. This will provide the initial grid to use while making your map.
Once you have your type tiles in place, you can use the Make Map menu to create a new clipboard map to replace the bare grid template you used initially. The larger you make it the more detail you can see in the editor, experiment with a couple of sizes. Rename the “map.bmp” output file and replace the map template file in your texsrc folder. You can edit the file with any image program, make notes, locate bases etc.
As soon as you’ve placed enough terrain tiles, place the three HQs, problems can result if you do not. These will become the Zone Masters, make the first one Bish, second Knight and third Rook. The map may still work if you don’t but it’s better to start with good habits.
This should get you started.