Install the latest OpenVPN package (depends on your Linux distribution).
Download the OpenVPN configuration files.
Unzip all *.ovpn files (each file is for one VPN server) to some directory. For example to your HOME directory.
Open terminal as a ROOT and change to directory which contain previously unzipped files.
Then start your openVPN connection in terminal using for example this command (czech server): openvpn --config eu_czech_republic.ovpn.
Enter your UnblockVPN Account details - your email as User name and Password.
If you can see the message "Initialization Sequence Completed" your openvpn connection is established.
If you have problem with opening pages. It is probably problem with automatic DNS or ROUTE configuration.
Please check your /etc/resolv.conf file and add right DNS configuration. You can use for example Free DNS servers from OpenDNS.com.