Want the easiest approach, provided you have a helper?

Remove the hood from the vehicle. Four pins and it's off, after you disconnect the washers.

Then, you can put it in a convenient place to work........just make sure you have a soft rug beneath it.

I found the pad completely deteriorated and a decent amount of rust beneath it. I also found the two supporting bars to be loose as the adhesive had dried and cracked.

So, out with the wire wheel and clean the entire inside completely. Get some epoxy adhesive and glue the supporting bars back to the hood (use some cement blocks to assure contact for most of the length). Then get some POR-15 and paint the hood.

Find an equivalent factory replacement pad on e-bay (the one with the extra reflecting piece of material) and use a full can of 3M super trim adhesive. The p/n on the can is "8090". Follow the instructions and put three coats on each piece........the pad and the hood........and allow to dry. Then carefully place the pad on the hood and press on all areas. It'll be there permanently.

Reinstall the hood in the vehicle.

I've done it both ways..........don't bother with the underneath approach........