Oversimplifying it, Ansible playbooks are nothing more than some commands that should be run on a remote machine via ssh. Ansible knows or has modules for a variety of different package managers (apt, yum, etc) and automagically knows how to handle services or various config files.
It can get complex, but I think just the startup phase, until you have an inventory of remote machines, the ssh keys are in place, etc. I second the Jeff Geerling recommendation, his stuff is solid, both ready to use playbooks, and tutorials.
I would suggest to also look into cloudinit
. Makes setting up VMs on proxmox easier, faster, more consistent, with users, networking, ssh keys, etc ready to use (by you or by Ansible).