Just give them a gentle tug, the rust usually gives way so no tools required haha.
Work front to back, wheels off for better access. Splash guards off, front arches have 4 10mm bolts but also 2 smaller higher up.
Side skirts, drill out the sill rivits and yank up, the clips are usually corroded anyway.
Rear under light trims, 10mm bolt from the tailgate side but need a yank backwards off the arch as the clips are tight.
Rear arches, 10mm bolts again, I'm sure there's one at the bottom of the sill?
Rear/front bumpers there's a 10mm either side but also bottom brackets, best to leave the brackets on the bumpers otherwise they just snap when removing.
Like Dave says, use plenty of wd40, ideally from the back side of the bumpers.
Have fun
