NEED HELP WIT MUSIC & MOVIES

ok well alot of yall advise did work, soo thanx to err one, anyways when i 1st got my instinct i loaded up the music from my printer and i saw the probs most of yall had and i did have em, cause i made alot of mistakes and could not format the sd card, soo i took it to a friend house and used his pc and now my sd card is blank, i know how to convert music and all dat, all i wanna know is in wat folder on my sd card do i save mp3's and avi files,