In one sentence, describe what the following article is about:

Take the fabric and fold it over the sides of the headliner. Use a pair of scissors to cut off the excess fabric. Leave a little bit so you can wrap it over the edge and attach it so the material is more secure on the panel. Do another round of smoothing with your hands to get the material as flat and even as possible. Try to match the overlapping of the original headliner fabric, if possible. Spray the adhesive onto the edge of the panel and the 1 inch (2.5cm) of fabric that's left after you trimmed the material. Fold the fabric so it wraps over the side of the panel. Use your hands to smooth it out. Don't pull or stretch the fabric or it can form air pockets between the fabric and the board. The folded bit of fabric will allow the material to stay better attached to the board. Use a utility knife or razor blade to trim the fabric covering the holes where the accessories, such as a light or a mirror, were inserted. Cut the fabric so it's flush against the edge and there isn't any excess material hanging over the side. Trim any of the holes in the headliner board that are used to insert accessories so you can install it properly. Turn the panel and rotate it so you can fit it back inside the vehicle with the fabric side facing out. Move any trim or accessories that may be in the way so you can replace the panel back to its original position. Be careful not to bend or scrape the headliner. Replace the visors, lights, trim panels, grab handles, and any other accessories that you removed in order to pull out the panel. Make sure the screws or bolts are tight and secure so the new headliner is held firmly. The new headliner will be held secure by the accessories and trim.

Summary:
Cut the headliner fabric so it hangs 1 inch (2.5cm) over the edge. Glue the edges to the other side of the panel. Remove the fabric covering the holes for the accessories. Insert the panel into the vehicle. Reinstall the trim and accessories.