UnderstandingCeph
Before playing with Ceph...
... it's important to understand its basic concepts. You will find a very good introduction in this video (quite old, but most of what is said is still valid). They are presented with more details here, in the official Ceph documentation website.
If you prefer books : Learning Ceph.
This wiki is useful if you want to learn by the practice on a Ceph testbed made of VMs.