Ideally you will need to wait until 6 weeks after your females spay to bond them. If you choose to bond them before she is spayed it will need to be 8 weeks after your boys op as he can remain fertile for up to this long. Once her hormones kick in they may fight and then you will need to separate and attempt to rebond once she has recovered from her spay.
Bonding should be done in a small neutral space where neither bunny has ever been before. The best way, in my opinion, is to put them together and keep them together, supervised, in the neutral space for a few days until they have gone 24 hours with no humping or chasing etc. (obviously separate if here are any fights!) there are lots of helpful threads on bonding if you do a search :wave: