Hi Arizona,
Did you also get the little plastic pad retainers? If not, get some new ones. I believe our hosts here have a kit.
Next, it's easiest when everything is cleared away from the firewall.
Remove the glove box and the heater box and the fuse panel. ( just take the fuse panel off the firewall, you don't need to completly remove it.)
Start laying the pad in position. When it's close, take the first retaining pin nearest the center. Some folks sell an installation tool, but if you have a nail setter, (flat center punch), that will work fine. Place the nail setter in the plastic retaining pin and using a hammer drive it into one of the original pad mounting holes nearest to the center of the pad. Then repeat as you work your way from the center to the outter edges of the pad. The pad installation takes about 15 minutes in a cab with an empty firewall. Total install time should be around two hours if you are removing stuff and re-installing.
Dennis