If you really want to alter game-mechanics, in other words create a mod, you have to alter the XML-File in the map-folder.
To do this open it with a program, I prefer Notepad++ (free download), and change what you want.
The XML of map PactofSteel2 has almost every game-possibility explained, so is like a modding-guide.
http://triplea.sourceforge.net/mywiki/Forum has lots of threads about modding and people who can help out if you get stuck.