The controls are configurable per-aircraft, so none of the following is set in stone. But for stock RealFlight aircraft, at least, we tend to set them up as follows:
The upper left 3-position switch is used for flight modes in helis (normal, idle up 1, idle up 2). For airplanes, it is assigned to miscellaneous special functions (this is uncommon).
The left front switch is mostly used for dual rates. Up selects high rates; down selects low rates.
The knob typically controls flaps for airplanes that have them. Turned all the way counterclockwise raises flaps (turns them off), and fully clockwise deploys flaps. The knob is not typically used for helis.
The upper right switch typically controls smoke or retracts for airplanes that have one or the other. It toggles throttle hold for helis.
Other notes:
Aircraft descriptions generally note anything special about their controls. You should review the description for each aircraft you wish to fly before you fly it.
The newer InterLink Elite actually has labels like you describe.
RealFlight 7, the latest version, contains a handful of helpful training videos--viewable within the software--that cover some of the basic prerequisite RC knowledge and InterLink controls that you need to understand as someone new to the hobby and the software.
You will find there is a lot of terminology and a lot of basic concepts you need to understand in order to be successful in RC. For example, I would not expect you to understand what low and high rates are for or how they work. That sort of thing is beyond the scope of the Knife Edge discussion forums. Luckily, many great resources exist online to help you learn.
Good luck!