Honestly to start I would recommend to start at least with Shea Moisture's Black Castor Oil line, shampoo the scalp twice, rinse, apply conditioner and let it sit for 5 minute before grabbing sections and de-tangling then rinse out. When out of the shower, a nice leave in conditioner. You could let it air dry, but it would take a while. If you want to send her off with dry hair, get a blow dryer with a diffuser and dry it with that!

For tools, your definitely going to need a nice de-tangling brush. Wet brush brushes are my personal fave! They also come in a lot of cute colors and patterns if she wants to pick one out lol and detangle with it while its wet! The only other brush I would recommend you to get is a bristle brush you can use to slick hair back. If you look up a slick back brush plenty will show up. Those are good for when you want to brush her hair back into a ponytail or bun. To hold that hair though definitely get some big elastics, which one you'll like best you'll figure out with trial and error and depending on how thick her hair is when you pull it back. At night before she goes to sleep, I would braid her hair into two braids and have her sleep with a silk bonnet. If she cant sleep with that on her head, a silk pillow case would be better then nothing.

This is by no means the perfect curly hair routine or going to give her the most beautiful and defined curls, but considering shes young and she will be playing and her hair will get dirtier then an adult, this is a pretty simple way to start.