We named one file mission1.map and the other mission2.map essentially and then copied eachothers folders and placed them in the the mission docs folder then went into the editor loaded the first and clicked merge, selected the 2nd file and they merged together on the map.
If I'm not mistaken, if you place a warfare module on the map, everything warfare is ready to go unless you want to get really fancy with it.
Since you are new to editing, take a look at Mr. Murray's Editing guide.
It's for Armed Assault but it'll transfer over to Arma 2 and OA. The Arma 2 and OA specific commands can be found here: