You can now lift straight up on the back plate and separate it from the body. Be careful to raise it gently because on the left side it is still connected with a ribbon cable to the main pcb.

There is also a metal bracket that drives straight down into the body on the upper left. Be careful to lift straight up on the back plate until this is completely outside of the main body, then flip the whole back plate over to the left so you can reach the ribbon cable connector underneath.

This is a snap on connector that can be gently pried up with a small flat head screw driver or a thumbnail.