Turn the power off to your Optoma projector. Unplug the power cord from the wall outlet. Let the projector cool for at least an hour.
Loosen the two screws on the bulb cover with a Phillips screwdriver. Open the cover to access the bulbs. The cover is hinged to avoid misplacing it.
Remove the two screws from the bulb unit using a Phillips screwdriver. Safely set the screws aside. Grab the handle of the bulb unit and lift it up out of the projector.
Insert the new bulb unit in the same alignment as the one you removed. Secure the unit with the two retaining screws, tightening the screws with a Phillips screwdriver.
Replace the bulb cover and tighten the screws. Plug the power cord into the wall and turn the projector on to test the new bulb.