Are you trying to play these in multiplayer or single player in the regular "random map"-type game mode? You don't actually need to create a random map to play your scenario multiplayer. Just host an Advanced Setup game, and under Game Type, where it says Supremacy, select Scenario and choose your file. It will get transferred to other players as well. For single player, first open the scenario, go to Player Data, and for each computer, press AI, select aomdefaultai.xs from the list, and press Open. Then go to the main menu, press Single Player, press Load Scenario, choose your scenario and you will play against the computer like in a normal game.
A random map must be created by writing a Random Map Script (RMS), a sort of program in text form that tells the game in what way to lay out the land, place units, etc but doesn't give specific locations like a scenario. It's pretty complicated and you probably don't want to do that unless you have an idea for a map that should actually be different each time and it's something you can't do in the scenario editor. A RMS tutorial can be found at http://www.mrfixitonline.com/aom-rms.asp.