My '97 K1500 truck was pre-wired. I'd assume the burb to be the same.
In the wire loom on the driver's frame rail, cut/dig back a few inches from the end (near the bumper), and locate the red and blue wires. If they are installed, that is where they will be.
The other end of those wires are in the loom underneath the brake booster. It will take a little digging to get to them, then pull them out. If I remember correctly, there isn't quite enough wire for the red to reach the aux stud (oh wait, the pre-96 doesn't have this, does it?).
Add an inline fuse or circuit breaker on the red wire and attach to the pos battery terminal, after the wire is made up on the plug.
Connect the blue wire to the output from the brake controller.
There is not a pre-wired harness and plug for the brake controller. You will need to source a 12V source, ground, and the brake pedal signal.