=OSX versions 10.11 El Capitan,
10.12 Sierra and newer=
If you have El Capitan
or Sierra or newer, then the built in VPN connection settings should just work. If you're not using Let's Encrypt then you will still need to install the Certificate as abov. You can skip the StrongSwan parts below and just use the Network Settings to add a VPN IKEv2 connection.
==Create the VPN Connection==