Oh hey, ClockJoule! Nice to read you in the Dzogchen forum! I always felt it was just a question of time until the sirens of the Vajrayana issue a call to you :)
Preliminaries in Dzogchen are not a simple subject, because you have different kinds of preliminaries depending on the lineage. Some use the tantric ngondro, some use the "Dzogchen ngondro", and there's actually more than one of those as well. So, not the easiest situation to get started in, but no worries - somehow it all seems to work out in the end!
It's not a bad idea to spend quite a bit of time studying, at first, to really work out the view, and also to work it into your mind. Actually, the process of working out the view obviously goes on all the time, perhaps until buddhahood is attained, it's just that it's always a good idea to strengthen your game in this area, because it expands your capacity to put the teachings into practice.
You don't need to go on retreat to practice Dzogchen. In fact, Dzogchen is the perfect teaching for everyday life. A retreat may be called for at a later point, when practicing the pinnacle techniques of Dzogchen. Not saying not to go into retreat, just that it's not really necessary the way it might be necessary with, say, Goenka vipassana or something of that nature.
Because I really like you, I will share an absolute gold mine of a resource, albeit I am slightly hesitant to do so, seeing as James Low is a bit of a hidden gem, and I am sure that's not a bad thing. Nevertheless: