Part of Betatesting is finding out. ie what people have trouble with, and then writting a manual. At least I believe that's Dave's logic is. Having the testers call and explaining to them the ins and outs, and then when they call back with updates, he can more accurately write a manual with recommendations, on where to start, and what the average guy might do wrong, or be confused about.
FWIW, there is a Power on switch for the display.
To scroll forward press the R/H touch pad. To back up the L/H one. To change an entry, depress the center button, the variable will begin to flash. When it's flashing you can increase the value with the R/H key, and deminish it with the L/H key. When done hit the center key and the entered value will stop flashing, and then you can again scroll. When done advancing thur the screens, the Save Data screen will flash, again press the center key. The touch pads have a slight delay in them so it may take one or two touches for the touch to register.
Be sure to write down the initial values, so you know where you started from.
HTH