upholstery tools are helpful but not required. The little staple clip things suck but it's really just a matter of removing the retaining clips and rolling back the cloth. replace with new foam, (I would cut to fit from generic upholstery foam to keep cost down) but hog ring pliers at the least would be worth the investment.
robbed this from fullsize bronco forum:
Cost me $20, but got enough to do both seats twice over. The special glue will run you $5.00 and last you for 15 projects. The hog ring pliers were $10 IIRC and a box of 100 hog rings were way less.
I cut three pieces per seat. One for the middle, and one for each side bolster area. Just try them first, shoot the glue on both seat and foam bits and stick em' on. Slip the cover back over and hog ring em' back on.