I dont beleive there is an official volvo way. 164 greenbook says refer to road authorities requirements. Silent on it completely from what I can see in the 240 greeen books.
Greenbook on 240 servicing just says to 'check alignment' but goes to great length detailing every other service item check.
Short of using a headlight alignment tool at a workshop, it just a matter of finding some flat ground with a wall to point at about 5m away.
Lights should point straight ahead and the cut off for the low beam should be slightly below horizontal.