2016 Peterilt 337 with PX-7 remote throttle

I'd like to install a remote throttle switch. This truck doesn't have the optional 12-pin connector for remote PTO/throttle from the factory. How do I wire up a remote throttle switch? The Body Builder's manual shows the pin-outs for PTO install without the optional 12-pin connector (titled Basic PTO setup without PTO Provisions) and on that connector, I see a pin labeled Remote_Throttle_Enable, but what do I do with that pin (do I ground it out or do I give it reference voltage from one of the other wires)? And what happens when I enable remote throttle (does it actually increase throttle or just enable that function, still requiring more connections to command the throttle increase)? If it had the 12-pin connector, you'd use 3 wires to a momentary switch to bump the throttle up and down. I found exact instructions on how to do this with the 12-pin, but this truck didn't have that option installed.