To install a standalone version of VPN Unlimited on your Linux computer, follow the next steps
Right-click the downloaded package and select 'Open With GDebi Package Installer' from the menu.
In the opened window click 'Install Package'.
Input your administrator password then click OK to proceed.
Wait till the installation finished, then click 'Close'
You will find the installed package in Applications -> Internet -> VPN Unlimited. Click it and follow the instructions of the wizard for setting up a VPN connection.
How to install a package in case of any problems or without a GUI using the console
Open the terminal
Type and execute su or type and execute sudo -s
Input your admin password
Type and execute dpkg -i package_name.deb
Type and execute apt-get -f install