I actually found the Mikrotik CLI easy to learn because it and the GUI are basically 1:1. For example: /ip/firewall/filter add is in the UI under the sidebar

I actually found the Mikrotik CLI easy to learn because it and the GUI are basically 1:1. For example: /ip/firewall/filter add is in the UI under the sidebar IP -> Firewall, then the Filter tab, then click add. The parameters are named the same in both too.