Trying to reconnect radio – Nissan Maxima Not sure? 2000

First post, forgive me if I break any general guidelines. I am trying to reconnect my radio after unplugging it for reasons I cannot recall. I have provided some pictures here:

I believe I am capable to reconnect everything I just need some advice on which wire goes where (I am aware that the square plastic pin thing with like 30 wires only has one obvious location), what I struggle with is, 1) what to connect the wire in the first picture to, 2) what to do with the wires coming from the back of the actual radio, 3) what to do with the two black wires (male and female in the 3rd picture), 4) and what to do with the red and black male ends shown in picture #3. Any help would be greatly appreciated!

P.S.

I can provide more up close pictures if needed.

Brand: Nissan
Model: Maxima
Year: 2000
Engine: Not sure?