Lets say your aircraft has a directional gyroscope, "DG", and a fixed card ADF.
Firstly, ignore all the compass numbers on the ADF indicator card as they are near useless. The ADF indicator index markings are quite usefull - the ones at 45 degrees, 90 degrees etc.
In your mind, transpose the ADF indicator needle onto your DG. Read off the number under the TAIL of the ADF needle and you know which radial you are on from the NDB site.