linux – StrongSwan Implementation on Lanner FW-7525 devices

I have two Lanner IP-Encryptor (FW-7525) devices with Installed Ubuntu 18.04 servers in both of them. Then I install and build StrongSwan in both of them. I connected one Lanner Device to one LAN connection and other with other LAN Connection. And see their outputs through console port on TeraTerm. How do I connect both Devices to create a secure VPN Tunnel with respect to both hardware and software.

Kindly give me suggestion.