so my cavalier has been a long term project, but after getting it jumpstarted on the old battery and driving around the block, we came back and disconnected the alternator and since it continued running, my friends and i decided that it must be the battery. i am admittedly not a car genius but it made sense to me. so we went and got a new battery, but now absolutely nothing is connected electrically, all we did was disconnect the old battery and reconnect this new one, and now no electricity runs at all. the dinging with the door open doesn't happen, no clicking when i turn the key, nothing. it seems like a lack of connection to me, but all we did was disconnect the old battery and reconnect a new one and now it wont do anything. i'm thinking corrosion but it visibly looks clean, also the positive connector has an extra wire hanging off that i can't seem to understand. all help is greatly appreciated, thanks!
ps: nearly brand new starter and alternator in the car