So , there is a difference between GA and small commercial flights. On the stand, you can switch between GA and commercial flights.
GA flights come by themselves and stay for a few hours, requesting fuel, and then leave requesting deicing if it’s cold.
Commercial small flights arrive when scheduled in the flight planner, and let of passengers and board passengers. They request fuel, being checked by ramp agents, and baggage service. This affects your commercial flight rating
You just need to toggle your small stands to GA mode, and then provide fuel service (avgas type).