I can only say what I do, I put the female near his tank for 2 days so they can see one another, then I put her in his tank for 5 minutes only, my boy did not like the Styrofoam cup, so I used a piece of plastic cut into a square with a hole cut in the middle for easy air.
After the quick visit, my male started blowing bubbles, the next day I put her back in with him and watched, if he chased and only managed a nip here and there I would leave her in there, I watch the whole time.
If he is still to feisty I take her out for a few hours then later return her, by that time he is well on the way to making his nest. I watch right up until she braves it to go and look at the nest and rub on the male, then she flits off, she waits until he goes to her and does his little dance, that is when I leave them do their own thing.
Got to the point they lived together in the same tank just fine, not trying to nest, but as soon as I put the piece of plastic in, they started nesting straight away.