Flip the projector over and turn around so that the lens faces you.

Twist the gray zoom adjustment ring clockwise and extend the lens all the way out, and then slide the zoom adjustment ring all the way towards the end of the lens as far as it will go.

Slide the front case plate towards the loosened zoom adjustment ring, until the top plate of the projector is freed from underneath the lip of the front case plate.

The front case plate will not come all the way off due to the zoom adjustment ring obstructing it. It will merely slide forward a bit.