Determine which earbud goes into which ear. Each earbud is marked with either an "L" or an "R" to signify left and right, which lets you know which ear to insert each earbud into.
Apply gentle force, and insert the earbuds into your ears. The earbuds should rest snugly in the outer areas of your ear canals. If the tips of the earbuds are made of foam or another soft material, pinch the earbud and insert it into the ear, letting the material fill your ear canal. If the earbuds feel loose, apply a little more pressure.
Place the audio input connection at the end of the earbud's cord into your mp3 player. Turn on your mp3 player, and make sure your connection is correct. If your earbuds have one cord longer than the other one, they are meant to be worn with the "V" part of the cord behind your back to allow movement.