To modify unit stats (like attack and defense etc.) you'll need Gnome Editor. There are already plenty of guides on tips on using the editor. It's found in the link on Alexandrapolites's post. It's called " Gnome_UnitBuildProj_Editorv2.0.zip ".

It's a pretty straight-forward utility. About the map editing, well BKB should know all about that after his release of his mod, the Age of Warlords.