It could be a lot of things.
Since it tried to start, it's probably in park (or neutral) but just for laughs, move the shifter in and out of park and try it.
Next check if the battery is good. Try the headlights and check the voltage. You can get a cheap multimeter at Harbor Fright if you don't have one. (and you should have one if you own an old car)
Next is to check the battery connections. They should be clean and tight. Same for ground connections to the engine and power connections to the starter relay and starter.
Next is the starter relay. There is one large connection and next to it, one smaller connection. Jump those with an old screwdriver and see if the starter turns.
After you've looked at those things, it might be the starter... If you can reach them, take that old screwdriver and jump the two connections on the starter and see if that does anything.