Click on 'System Preferences' and click on 'Network'.
Add new profile
Click on "+".
Select the "VPN" in dropdown menu as Interface and "IKEv2" as VPN Type. Enter service name you want and click on "Create".
You can find all available servers in the members area when you logged in and put the alternative server address as "Server Domain Name" and 'Server Domain Name' as "Remote ID:". Then click on "Authentication Settings…".
Route to all
Tick "Send all traffic over VPN connection" and click "OK".
Enter your username, password and secret key
Click on "Authentication Settings.." and enter your account password. The "Shared Secret" tab should be "veripn"
Click on "Connect" to start VPN.