You'll figure it out by trial and error-what your bird likes and what makes it happiest if you pay attention to her body language, play time, etc.
I have read the "ideal" you should have is a bath tub, at least 3 different perches, a ladder, a swing, at least 3 toys, something to shred and something to forage in. It is also good to rotate different toys every 3 days so they don't get bored or become territorial.
I follow the above and use veggies as added toys-she loves to shred & munch long strips of broccoli, celery, parsley, kale, spinach, wheatgrass, & romaine lettuce.
Not only do I hang veggies from the side, but she has movable toys that clip onto the side-one resembles a toy lawn mower with a bell inside that she likes to spin, an orb of movable rings she likes to spin, a bell with tassles, a play perch with toys on & in it, and a few others I don't know how to describe.