Advice needed

I’m Wendy, a new and expecting bird mom. I just bought a pair of 15 month lovebirds from a local pet store and plan to pick them up Friday.

The birds were hand fed however, they are not fully tame and sex is unknown. They don’t bite, but can't step up on a finger. When I played with them separately, they liked to fly away at first and after 10 minutes they were relaxed. Should I keep them separately for a few months? How long? Will they fight if I reunite them? What about advice for keeping them together?

I hate to back out of the sale because the woman that sold them to me was very kind, but I’m worried!

Also, can you recommend me some training videos or instructions?

Thanks!