Great, thanks for that - I haven't flown for 6 years so haven't used it for 6 years, and am renewing my license so it's just requiring a lot of remembering and retention and even basic things like that are proving frustrating at the moment!
Get out your favourite flight simulator program (most likely MSFS or X-Plane). Put the plane in slew mode so you're not being affected by all those pesky laws like gravity and speed of light. Go to a position near a beacon, note the settings. Rotate the aircraft through the full 360 degrees and see what happens. Fly around the beacon, or over it, and see what happens. Fly directly to/from VORs, NDBs trying to make a straight line on the map. Do a mock flight from A to B to C, noting the needle and OBS positions in the process. Try to navigate back to A without using anything else than VOR/VOR, VOR/DME or NDB/DME. Let somebody put the plane in a random position over an area for which you have the paper ICAO VFR chart. Without looking out the virtual window or looking at the virtual map, tune to a number of likely VOR frequencies, ident them, take their bearing and then draw all these bearings on your chart. See if you can figure out where your buddy left you. Then, do the same thing but with NDBs exclusively.
Learning radio nav is the one thing where investing, what, 40 pounds or so in MSFS really pays off.