Need to change my BCM

It does not have a single BCM. It has multiple SAM modules around the vehicle that each handle different duties.

Okay, my windows, seats, locks sunroof, signals, and horn are all out. what might be the problem?

That is something that is going to require an electrical technician to follow wiring diagrams to the source of the issue. About all you could do yourself is to test all the fuses in the car using a test light.