how do u give rain its sound.

Im dumb is this already ingame? If not i think u'd need to make a track with a raining sound play or for a certain place you could place a region (somehow) where the soundtrack would play.

Yes, you can either create some regions or make it the background music. The first choice is the best option. There doesn't seem to be a tut for sound regions, so how I learned is by checking out the tatooine map. And going into the soundregion layer.

i did that and it still no sound. plz help!!!

The best world to look at for rain sounds is Kamino. Look at the soundregions level.

But wait that is not all, the fun part of BFII is not all the sounds are included in all world sound lvl files. In order to get the rain sound you may have to change which sound lvl file is loaded in your LUA. Once again I'd refer to a Kamino lua to see which sound lvl file they use and change your lua accordingly, this includes the sound calls lower down in the file for ambient music etc.

The other way is to make a custom sound file with all the effects and streams that aren't in the one you want to use but unless you are experienced in making sound files I'd go with my first suggestion.