Unbolt the seat from the truck, don't forget to unhook the plugs for the power motor and heater
Flip the seat over
Using a decent pair of pliers you can unhook the remaining springs and replace the foam.
I went to an upholstry shop and picked up a 1 1/2" dense foam, cut it to size myself.
While you have the bottom undone check your wiring its easy to see and get to.
When reassembling, put a piece of burlap, rag, material of some sort between the foam and the wire and springs.
It took me about an hour to do the foam in both front seats. I also touched up the frames while I had access.