Ec2 VPN tunnel with a remote server

Complete beginner question:

I have an EC2 instance with an elastic IP and some port open.

I want to create a VPN tunnel with a remote server.

The VPN as already been set up on remote server.

I have the public IP, a key and the open port of the remote server.

I have installed openvpn on my ec2 instance and i have access to their UI.

Where do I go from there ?