On the apple menu ,located in the top-left corner of the screen click on System Preferences

And then click Network

In Network window click on the + symbol to create a new connection. Next in the dropdown menu select interface as VPN then choose VPN Type as Cisco IPSec then click on Create

Server Address : one of the zebravpn address (it will be found in client area)

Account Name : It's zebravpn username For Password : Enter your zebravpn password account

For Entering secret click on the Authentication Setting Enter secret (secret will be found in client area)

Click on apply to information be saved.

Then as last step click on Connect for connecting to server.