That is really up to them. They must live in separate cages and have time out together every day. You MUST stand right there, completely supervising this time out, ready to rescue a bird if they start fighting.
Once you see they play well together and enjoy being together, you can allow them to play on a cage and put food and water inside the cage. This allows you to see if they will go inside and not fight over the food and water or even the cage.
This could take days, weeks, or even months. They may NEVER want to be together.