Radio/Nav in the PPL syllabus is designed to suppliment VFR navigation (map reading). As you cannot see anything useful out of your simulator window, it really is not much use at this stage.
There is no point learning to track beacons and fly with your eyes in the cockpit when the intention is that you obtain a bearing or series of bearings to verify which town you are looking at out of the window.
Simulators, STDs and PCs etc are very good for practicing procedures; but there are no procedures in the PPL syllabus, other than being able to track towards or away from a beacon; to stop you flying past the airfield you really want.
You could of course practice obtaining a VDF bearing; most students don't seem to have a clue about this simple procedure.