How to build a Navigator House?

Hey, I'm brand new to all of this, and some friends this weekend have convinced me to try my hand at it. I've played the heck out of the Rogue Trader CRPG, and I'm fascinated by all the lore about the Navigators and the houses of the Navis Nobilite.

Does anyone have any tips on building an army themed around the Navigators of a house and their house's retinue? My current plan is two or three Navigators plus a free trader entourage, some voidsmen-at-arms, and some imperial breachers. I know that's not everything I need, but I don't know what else. Also, how do I get my hands on multiple voidsmen-at-arms squads when they seem to be always packaged with the rogue trader entourage?