Carenado c90b pressurization system?

[rwat 1]

The pressurization system in the carenado c90b does not seem to work like the real thing, I looked at a tutorial online for operating the pressurization system in a real king air and the carenado version does not seem work like the real thing at all. For instance the carenado versions cabin rate of climb decent knob works in feet per minute while the real thing is an adjustment for how fast the cabin descends or climbs in relation to the aircraft. From what I have gathered if you are flying at 20000 feet but your cabin altitude is at 10000 feet(for easy math this is obviously way too high) the pilot would usually have the cabin altitude descend at half the rate of the aircraft so if you descend at 1000 fpm the the pressurization system would usually be adjusted to descend the cabin altitude at 500 fpm. Also the cabin altitude works by selecting the cruise altitude you will fly at on the outer ring of altitudes while the inner ring of altitudes will be the pressure altitude the cabin will be kept at. But the cabin altitude gauge shows the altitude selected on the outer ring so my cabin altitude has to be 10000 feet or higher??? am I doing something wrong or is the function of the pressurization system wrong? I I am operating it incorrectly any advice would be appreciated.