Tips on headliner replacement will depend on whether you have a solid base that you just want to cover or whether you have to cut and fit hard materials to fit inside the raw fiberglass.
If you are just wanting to cover with headliner material, take a look at the videos at Sailrite.com on the subject. In addition, they sell a wide variety of applicable materials including the spray adhesives and selection of carpet-like or conventional vinyl headliner materials.
Here's a collection of videos on the subject at Sailrite: Headliner videos
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