It can take up to 48h (rare) that she feeds them, most do it much earlier. If the kits are in nice, dry nest (check that) covered with fur and the doe is clean and relaxing just feed her well, a lot more than she usually eats and unlimited hay.
Let her rest and give her privacy for nursing - my does don't go anyway near the nest while Anyone is around, I very seldom notice them nursing - and that's only when I come around when she has already started.
Breeding and raising more bunnys is what rabbits excel at, most times there isn't any intervention necessary.
I let the does decide when to wean, I just seperate the bucklings at 12 weeks (bigger breed, they don't mature before 16wks, with small breeds 8-10weeks would be the time to separate). When circumstances demand it it's ok to wean at 4 weeks, like when the next litter is about to be born.