On the bottom of the camera, next to the hot shoe is a small metal piece with a circular tab on it.
Looking at the bottom of the camera, with the hot shoe to the left, push the tab upward. The back should now slide off.
When you load the film, extend the lens and lock into place. Don't use an excessive amount of force to lock the lens.
The shutter must be tensioned to collapse the lens.
When shooting, if you reach the end of the roll, don't force the film advance lever -- you'll break the film advance mechanism.