1.) open up your Nexon folder wherever its at because mine may be in a different spot then yours and I dun wanna confuse you.
2.)Open up your game folder then press BGM which stands for Back ground music.
3.) create a new folder name it whatever you want I named mine Backup folder because this will be your backup if you ever want to have your old song back.
4.) copy and then paste your waitingroom_loop and UIbgm_loop into your folder whatever you called it.
5.) open up firefox or internet explorer go to Beemp3.com type in your song or artist double click the one like this for example
6.) save file to desktop.then drag it into your bgm music not your backup folder.
7.) go to your waitingroom_loop mp3 majiger rigth click then press rename copy its name delete it go to your thingy the song what ever you chose that you placed in your folder press rename paste that in their.
8.) turn on combat arms
9.) get into a server.
10.)press a game anygame
11.) wait a second and you will here your music playing
12.) Thank me.