how to forward port for wireguard tunnel

Few days ago, i finally learned how to make tunnels between peers in mikrotik
Now i want to to make 1 router as server and 1 as client.
I followed this tutorial: https://www.youtube.com/watch?v=AR5IWUpZbsk
What i dont understand is how to forward port (5:10 at tutorial) in winbox.
Firstly, for which router i need to do this, server or client? And how to do this
At the moment whenever i active client wireguard, i dont have internet. For server its fine.

This explenation, which is part of the official MikroTik documentation, will explain exactely how to configure this setup:
https://help.mikrotik.com/docs/display/ROS/WireGuard#WireGuard-SitetoSiteWireGuardtunnel