Dismantle the (broken) cd/dvd player. You'll find a lot of interesting parts (e.g. the lens), but in this tutorial we need just one of the motors (usually are 2, and the damage is somewhere else, so they works). Take it out.
NOTE: every drive is different "inside", so it's a bit useless show you where is located. But you can see the picture to know what you are looking for.