rear window trim

[68r/t]

I have just purchased the plastic trim that goes around the back window and am unsure of how it is supposed to fit.
The elbow sections seem to long, do you have to cut these down to the correct length?
Do the elbow sections and the bottom straight section fit underneath the corner sections or are they  supposed to butt up against them?
I pulled my original and broken ones out a few years ago and I do not remember how they are supposed to fit.
They are Trim Parts brand moldings.

Thanks

[Just 6T9 CHGR]

The corners overlap the sides & bottom pieces..only the top buts together & the seam gets hidden with the small block

[dspaulding70]

Where did you get the trim pieces?