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.