seen a few posts lately from those just picking up new cars....now mine is a month old i feel qualified to speak at length as an expert
anyway i found that to get DAB "working" i just went into manual station selection, initiated a "SCAN" as you do with your indoors DAB at home. it then "scanned" and found lots of different station categories which i then saved under the available presets. now whenever i go into DB it auto rescans and picks them all up again.
if you don't do this then you just the the presets with "no signal" listed against each one, it doesnt seem to go off and find stations for you (as FM does with autostore) without you telling it to.
edit: I was totally unimpressed with DAB for the first few uses....now i've sussed it (sort of) i love it!!! good option to have.