I think the step by step recommendations for bonding are helpful, both in that section and most likely described on the HRS site, http://www.rabbit.org.
I also would suggest that you read a few posts in the Bonding Forums, which describe similar starts and answer similar questions. I am thinking of Beka’s bonding of Max and Meadow as a really good example of a good bond procedure, and Mark’s for a good example of a very difficult, but ultimately successful, bonding process.
They need their own space, they need to be spayed and neutered, and you want about 1-3″ minimum between them at all times to avoid bites and other potential harm by being too close when unsupervised. Personally, while the bonding sessions initially take place in neutral territory, like a bathroom or a hallway, if they become familiar with each others’ scents in your communal spaces as they take turns playing, and they don’t get territorial by marking or acting up, then you have made good progress. You can put a surrogate toy in each cage, then swap them out, to further their familiarity with each others’ scent which helps them accept the real deal more readily. Also, if one decides he doesn’t like her, or vice versa, it can take the aggressive behavior and you will know who may need watching during the bonding sessions.