Star Wars Battlefront 2: How To Play Mod Map Sides On Stock Maps (HD)
Channel: MikeTheBeastsVideos
Date: 23/04/2016

Not too much to say here other than just follow this instructions and you will be fine. BE SURE TO NOT DELETE OR REPLACE STOCK FILES, IF YOU DO THE ONLY WAY TO GET THEM BACK IS TO REINSTALL THE GAME!!! This might take you a few tries to get it right so go slow if this is your first time, most likely it is. 

Steam Instructions: Follow this Path: C:\Program Files (x86)\Steam\SteamApps\Star Wars Battlefront II\Gamedata\data\lvl_pc\side and do what I told you afterwards