When towing a Imagine 2500rl travel trailer and setting the Gain controller for the travel trailer brakes on a 2020-21 ford F-150 truck, is there a confirmation button you need to confirm the Gain number OR is it automatically saved in the Tow Haul screen?

I have no problem adjusting the Gain, I can't seem to find any button to push to save the setting?
Its my first truck so maybe unlike the older models there is no SAVED button.
Hope this makes a little sense.

If you know anything about this I would appreciate a shout out.
Not sure but I think I drove 500 miles with only the truck brakes working.
Actually it worked out okay but I know this should not be the norm.

Thanks in advance.