I remove the rear liftgate speaker cover from the panel. Then plug in the light harness, then make sure all the panel clips are in place and start from the rear and push up and towards the front of the car (This will ensure that the two plastic guides on each side go into the slots, then push the panel clips in. With the speaker grill removed you can use you fingers to ensure panel clips on the inside (near the speaker grills) are nice and tight. Then screw in the screws on the panel ends and you should be good to reattach the liftgate smaller panels around it. Make sense? maybe not ,but when you have done it like 20 times there is a right way and a wrong way to get everything in place.