If I were you I would leave the rear seat out for more cargo room. That's what most people I know do w/ wranglers.
Anyhow each side has 2 brackets. The one on the floor has little axles that stick out for the seat to slide on and off as well as hinge up and the ones that get mounted on the wheelwell are horseshoe shaped to catch the rod that sticks out on the seat and lock it in place. Horseshoes face open toward rear of vehicle. See attached pics and schematics from google.
First pics is from a CJ but it is the same as a YJ except mine doesn't have lap belts, they're mounted to the rollbar.