ok so basically to play a sound or music in your game, you have to have the sounds music files, in WAV format, not mp3 , and have bit rate of 16000 hz not 25.k not 8k 16-bit rate that's if u converse it with audacity ul have options in bottom left.
then c2 automatically converses them to 2 files 1 .ogg and 1 .mp4, the .ogg is for html5 browsers facebook etc the mp4 is for mobiles when u play audio u need to add the audio object and then call a condition when u want to play it lets say at start of game : when layout starts >audio|>play sound, your sound... and if u want to loop it loop it if not will play 1 time.
also when u run your game you have a game property saying preload sounds at startup , that means all sounds will be loaded when ur loading bar shows at startup so it does not lag ur game, during gameplay or menu show.