How do you play a map for Star Wars battlefront 2 after you downloaded it

if you mean how do you install maps to play them these are the steps,
first make a folder called addons in this folder

c:Programmefiles/lucasarts/starwarsbattlefront2/gamedata

then extract the zipped map folder and take out the file with three letters in CAPITALS

e.g YYY and put it into your addon folder.

i hope this helped, there is a video tutorial here if you didn't understand.

http://www.youtube.com/watch?v=7LZk-GOfsdI

(this is not my tutorial)