Hi, I've been playing the game for years and I think I can answer your question. First, you can not currently create a scenario against the computer AI from scratch. To create a custom 2-player scenario, select 2-player game, then select either Custom Scenario US Army, or Custom Scenario USMC (or Canadian/other equivalents). You will then be prompted to select a map, go to the MoreMaps? folder in TacOpsExtras? folder and select Map 780 (I'm doing this from memory, so the folder names may not be exact). Set preferences as you wish in the Options menu, and then select, also from the options Menu, either add one unit or add optional units.