I did this with my old S10, and it involved drilling holes into the frame to bolt the hitch to. I think the difficulty depends on whether or not the holes are pre-drilled. If they're there already, it should just be a matter of bolting the thing in. If you have to drill holes, you have to clamp it so that it's straight and level and then drill using it as a frame.
After I bolted mine in, I paid a welder $50 to go around the edges for me to make it more secure.