I got it! I used a flat head screw driver to push the tab and got the wiring harness unplugged from the truck. Then I unmounted the sleeve and the controller.
Now my problem is I can't get the little fuse box panel back on. I didn't pay attention to how it came off and I can't figure out which way to turn it.
I called e-trailer and there is no plug in ready to go wiring for the 2013. I think Chevy stopped the plug in thing in 2007 I read. Instead I would have to pull the wires and connect them and crimp. I have a built in brake controller already factory installed but wanted the prodigy. I can probably just give it to my brother instead and live with what I have.
Thank you for your replies!