Summarize the following:
A heavy duty fabric designed to be used as a headliner will last longer and will form a better adhesion to the headliner board. Be sure you use the correct material for the best fit and bond, and so the fabric won’t warp or sag over time in your vehicle.  Temperature fluctuations that occur in vehicles can cause other materials to sag. You can find headliner fabric at auto supply stores and online. Take the new fabric and lay it across the panel. There will be plenty of excess material hanging over the edges of the headliner panel. Smooth out the fabric so it lies flat. Check to see if the material has a front and a back end and make sure they correspond with the front and back of the panel. Take one edge of the fabric and fold the material back onto itself so half of the panel is exposed. Smooth out the fabric at the crease of the fold so the material lies flat. Working 1 half at a time makes it easier to attach the new fabric. Spray adhesive is an industrial bonding agent similar to glue that can be sprayed onto a surface to adhere it to another surface. Shake the spray adhesive well, then apply a thin, even layer on the exposed headliner panel. Then, spray the adhesive onto the folded fabric so the underside is coated.  Hold the spray can about 1 foot (0.30 m) away from the surface of the headliner and fabric. Use even, back and forth motions to spray the adhesive. You can find spray adhesive at home improvement stores, at department stores, and online. Unfold the headliner fabric and lay it back down on the panel. Use your hands to smooth out any creases or bubbles between the fabric and the panel so it’s smooth and consistent.  Push any bubbles to the edge of the panel so they can be removed. Smooth the fabric as long as it takes to make it completely flat. Repeat the process with the other half of the fabric. Fold it back onto itself, spray the adhesive on the panel and the fabric, then lay the fabric back on the panel. Use your hands to smooth out the material so there aren’t any trapped bubbles or creases. Don’t stretch the material or it could cause wrinkling in the fabric over time.

Summary:
Use fabric designed for vehicle headliners. Lay the new headliner over the panel. Fold half of the fabric back over itself. Spray an adhesive on the exposed panel and the fabric. Place the fabric on the panel and smooth it out. Pull up the other half, apply the adhesive, and attach it to the panel.