I know the feeling haha. When I came back to DA i was like "whaa? wtf do i do now". Well the way i did it was i first found some general "come alL" groups (either by other pictures already in those groups or by manually searching) and i submitted there. Then i started looking for more specific groups. This picture for example i'd look for photography aimed groups, macro and color. Once you join a few groups and grasp the whole concept of it it gets easier to get around.