Slick 60's

The back piece of the headliner (over the rear window), connects to the top piece using 5 clips. I cannot figure out how these five clips are installed. Short story: Bought the carpenter headliner kit and installed the top and two side pieces. Went to install the back piece and broke it. Bought some heavy paper paneling at Home Depot and cut a new back piece using the broken piece as a pattern. So far so good. I will soak this piece in ammonia for several hours before I try to install it. I have 5 small clips. These are not S clips like the ones used at the front of the headliner. These small narrow clips have a C section with a short tab on the other end. I cannot figure how these little buggers connect the rear of the headliner with the back piece. Thanks for any help!

I don't know if you can see in these pics. the clip slides onto the top headliner from window side the little angles go down and rearward, I taped my clips in plce, lifted the headliner up to clear the rear piece 'til they were behind the clips and let go.

Steve, Excellent work. Thanks for the pic's.
Bill