Very simply, you track towards the beacon (assuming of course that it is on the airfield) on a published radial that aligns with the runway. Descent is governed by published heights/altitudes at various DME from the threshold. For example the inbound QDM might be 180 degrees so you track towards the beacon on the 000 radial keeping the head of the needle on 180 (your heading might be offset to allow for any cross wind) and at 6d you should be at say 1800', 5d at 1500' etc until the minimum descent height which is again published. All the information is given in the Aerodrome section of the AIP, but Aerad or Jeppesen plates are more user friendly in the air.