Weeds,
The sides of the headliner pieces sit inside the groove/lip/channel that runs along each side from the rear door opening almost to the side door openings.
The rear-most piece of headliner fits into a groove/lip/channel above the rear door, and the sides fit in the channels/grooves/lips on either side.
The leading edge of the first four pieces are held up to the roof by screwing the bow into the rib in the roof, screwing through the headliner piece (and thus holding up the headliner piece).
I bought my headliner set from Jim Carter (about 6 years ago) and it did not have to be trimmed (except for the front piece - let's wait on that until you get there). However, the two forward pieces of headliner were cut too short in the corners.
Unfortunately, I did not take photos during the installation, but here are some photos after the installation.
http://www.1954advance-design.com/SubHeadliner/index.htmlTim
