ESky basically packages FMS with their controllers.

Read up on FMS ( google for it ).

Your biggest difficulty will be figuring out the channel assignments.

FMS is not that user friendly in this regard so you'll have to bring up a plane, and see how it responds to inputs.
Unfortunately there are no control surfaces to help you see what you are moving...

So if the plane vears right when you pull the right stick back, you know that the elevator and rudder assignments may be reversed.

You'll have to adjust accordingly in the FMS controller panel.

Do the same for the other channels until the plane responds correctly to inputs.