Click on the Ubuntu icon and enter the text terminal. Launch Terminal.
Install GUI package to connect to OpenVPN server with the following command:
sudo apt-get install network-manager-openvpn-gnome
Enter the password of the Ubuntu account to confirm the installation program.
Download OpenVPN configuration files for Tunnelblick Mac OS. And unpack the Zip file on your Desktop.
Click Edit Connections.
Click the Add button.
Select from the list Import a saved VPN configuration.
Select OpenVPN configuration file.
The following information look under "My Account".
OpenVPN connection is successfully created.
Connect to the OpenVPN server on Ubuntu.
You have successfully connected to OpenVPN server.