On the lower part, push down, and back. When it slides back, keep pushing back, but lift up on the front of that seat. Once it pops loose from the bracket, pull it forward. Sometimes it's easier to get out if you remove the armrests.
As far as the back goes, down at the bottom of both sides, it is attached. Earlier cars have a loop that has a piece of metal come through, and then bend to the side. Later cars have a bolt in the spots. I'm not sure where a 72 falls. Once you have it freed on the bottom, lift straight up, to free it from it's upper support.