First of all, there are five screw sizes you'll encounter in this guide. I'll refer to them as size 1-5 throughout this guide.

Far Left (size 1): These screws secure the mainboard. There is also one helping to secure the I/O plate.

2nd from left (size 2): This screw secures a ground wire to the I/O plate.

3rd from left (size 3): These screws are used exclusively on the I/O plate.

4th from left (size 4): These screws hold the projector's outer case together.

2nd picture (size 5): Two of these screws secure the yoke assembly.