might be fuses

I own a 1988 pontiac grand prix and I just put a battery in there and the door open sound comes on but I get no dashboard,no horn,no radio.Could this be the fuses?Or is something else the matter?

Possibly but check the battery connections at the battery and at the starter. It could also be a bad ground so check as many as you can find. The fact that you have no lights on the stated items could indicate a problem with the ignition switch as well. Not in the key area but at the bottom of the steering wheel.