Hi, I had the same issue, but it's actually very simple. The screws on the back of the speaker come down when you turn the plastic hook they're enclosed in out of the slot they are intially enclosed in. Push two of the screws on one side all the way down, and what they do is push the grill out. Do the same with the other two and the grill pops completely out. Put the screws back in place, make the hole in your ceiling, push the speaakers up into the hole, and screw the now uncovered screws on the face of the speaker until the hooks come down and secure the speakers to the sheet rock. You're done.
Good luck!