Tutorial on how to hire your own sims you made, to work in your Restaurant

Ok, so I have to delete ALL NPCs from the world, right? If I do that won't the world be totally empty? I mean there families that come 'installed' in every household, even though I don't play them nor interact with them, they have to be removed. Isn't it possible to remove them, add my 'worker sims', employ them and then move the families back?