Need help replacing spare tire bezel retaining clip and lock

[diesel427]

I replaced the rear bumper on my 2003 Tahoe LT with an aftermarket bumper. I got the bumper on with no problem. When it came to putting the spare tire bezel retainer clip and locking ring on it has been a headache. It keeps popping off when I try and push the locking ring into the retainer. Is their an easier way of installing this and does the bumper need to be off the truck for installation? Thanks