Help getting started with ROS and OSPF

Hi

Have used Mikrotik equipment for a while.
But have no experience in OSPF setup, and I`m now trying to grasp this.
I have several sites, witch I want to route between with OSPF and ROS.
See the drawing, each router is in a different site, but will all be in a different OSPF sone?
I have no idea where to even begin.

Can anybody show me how to do this, I will be very grateful :slight_smile:
ospf.png