Yes, it's does not want to grab on anything. I see there is a white "ring" that goes around the assembly that everything clips onto, and it seems like tag gets pushed up when I try to clip it.
See if this helps..... Look at headliner.
Yes, it's very difficult to get the light to push into it. I have the moon roof, so I was able to open that and get a big screwdriver in from above to hold the plastic ring down while I pushed the light up. I don't know how to do it without a moon roof. You may have to glue the plastic ring back down to the headliner first.