50 Kits Car Roof Headliner Repair Kit, 202Pcs Rivets Repair Button Auto Roof Snap Rivets Retainer for Interior Ceiling Cloth Fixing Repair Buckle with Installation Tool (Grey Grid)

The right way is a massive project. I did the quick and dirty way on a Mk4 and a Mk5 and it's lasted 3 years so far. Motormite makes part# 74360 or 74361. Most parts stores have it. It's a black plastic thumbscrew with a large flat base. You make a tiny cut in the fabric and screw this piece into the hardboard underneath. On VW you need to use a sharp pointed knife to make a small clean cut in the fabric rather than just a simple hole. Otherwise the liner fabric grabs the piece and twists around as you screw it in. I haven't tried this but it looks like a better, neater, way. Maybe? https://www.amazon.com/Headliner-Button%EF%BC%8CAuto-Retainer-Interior-Installation/dp/B0D879JHMP