I pulled the headliner substrate from the vehicle, removed all remaining headliner, sanded the old adhesive off (gently so you don't damage the substrate), then attached the new headliner. Lay the headliner down then fold it back on itself halfway and apply adhesive to both surfaces. Follow the instructions for the adhesive you are using for drying time before bonding the two surfaces. The reason I say it will take twice as much adhesive is if your headliner has a foam backing it will absorb the first coat and you will need to apply a second coat of adhesive. If you have any questions just give me a shout.