Print using medium or coarse quality, the model should be placed on the diagonal surface connecting the two mounting plates. Minimal supports are needed on screw holes and space for microswitch pusher only.
Screw laser module on first - 3,5 mm self tapping or M3 screw and nut. Use M5x8 screws to screw holder with laser on the gantry. The module should be about 5 mm off the plate when homing.
Look at the pictures to see if you have the right module. Mine was a cheap Chinese one (15W pulsed, 8W permanent power).