I've never sold coyotes hides...but I paid for my first vehicle (1973 Jeep) with fur money, mostly mink, muskrat, coon, fox, and possums (don't laugh, a big one would would bring $5 then)
All critters skin about the same...the hard parts are the tails on the ones with furry tails and the ears....I whacked the tails several times with a hammer, they pulled right through...ears, you just have to be careful and watch what you're cutting.
Stretching...I had boards cut to size for each critter, sorta shaped like a bowling pin but without the skinny neck, stretch them over that, clean them off, rub them with salt, let them dry.
Skinning...I believe there are videos on YouTube that might do a better job of explaining it.