Clever camper-van tricks?

Hey there, I hope question posts are okay. My fiancé and I are planning to turn our Dacia Dokker into this sorta mini camper amalgamation. Do any of you have experience with this sort of endeavor and can offer tricks or insightful knowledge?

Edit: I should add that it's supposed to be modular. So luckily (or unfortunately?) I don't need help on how to permanently fix furniture onto the car frame.