Lay the material over the H/L panel. You'll need it to be a couple of inches larger all around.
Roll it back 1/2 from side-to-side. Spray the glue on both the panel & the material. A very light coat on the material. Very light! Too much & it'll soak into it. Let the glue tack up some. Another light coat on the material. The first coat should be dry before the 2nd coat. The first one will help to prevent the 2nd from soaking through.
Start from the center & lightly press the material down, working to the outer edges. Repeat for the other 1/2.
Don't press the fabric down in the center too hard when doing the first 1/2. If you do, there will be a crease mark in the center.
The actual real H/L material is stretchy. To do the outer corners where the H/L is curved, hold the material up a bit from the panel & pull it slightly while pressing out any wrinkles with the other hand, working from the inside to the out.
By letting the glue dry a bit & by lightly pressing it down by hand, the fabric can be lifted if it's wrong or has a wrinkle with a quick snap up of the material. Rollers will leave marks. This is a job best done by hand & feel.
Once it's all down, then you can use more pressure by hand to get the glue to stick well.
Flip the H/L over & glue the extra material hanging off around the edges along with the back of the H/L about 2 or 3" up. Wrap the material around making any cuts or kerfs to allow the fabric to fit the outer contours of the panel. Small cuts at first. You can always nip them a bit bigger if needed. Too much of a cut & it may be seen when the H/L is in the truck. Multiple small cuts work better than one large cut.
Other places where the material bunches up can be squeezed together & then cut off flush.
After that, cut out the holes for the light & the visors. O/H console too, if you have one.
