The recommended way to set up Ceph is cephadm, a single-file Python script that is a multi-tool for both creating and administering clusters.

https://docs.ceph.com/en/latest/cephadm/

To learn about Ceph, I recommend you create at least 3 KVM virtual machines (using virt-manager) on a development box, network them together, and use cephadm to set up a cluster between the VMs. The RAM and storage requirements aren't huge (Ceph can run on Raspberry Pis, after all) and I find it a lot easier to figure things out when I have a desktop window for every node.

I recently set up Ceph twice. Now that Ceph (specifically RBD) is providing the storage for virtual machines, I can live-migrate VMs between hosts and reboot hosts (with zero guest downtime) anytime I need. I'm impressed with how well it works.

You could start by installing Proxmox on old machines you have, it uses Ceph for its distributed storage, if you choose to use it.

Look into the Rook project