Tips to install cardboard headliner?

The stock one that was in my 73 scamp was held in with the domelite, the flap from the windshield, the trim around the rear window and the long trim pieces that go along the top of the door opening.

I would get someone to hold it in place while you tuck the front under the windshield gasket and install the domelite, I have paid one of the neighborhood kids 5 bucks to help me before.