First thing is make sure openvpn is installed. Then download your config and .crt file from Private Internet Access the one that ends in .ovpn and edit it and add the following line without quotes "auth-user-pass private" save it then change the name of the ovpn file to something like PVPN.conf and then place it inside /etc/openvpn. Also copy your .crt file into /etc/openvpn and make sure the ca line points to it IE "ca user.crt" Then make a text file with nothing but the username and password in it no spaces just one on each line like so.
Name it private. change permissions on it sudo chmod 600 /etc/openvpn/private
You can start the service with the following command sudo systemctl start openvpn@PVPN.service
or enable it to start up automatically with this command sudo systemctl enable openvpn@PVPN.service
If you experience any lag or slow speeds you might try adding this to your PVPN.conf file
Of course if you are on a DSL connection your tun-mtu will be 1492. You may have to experiment. Lastly go to a place like speedtest.net and make sure your IP has changed and so has your geolocation. Restart the VPN with the command sudo systemctl restart openvpn@PVPN.service
If you use a firewall such as iptables the following rules should be sufficient to get you up and running.
iptables -A INPUT -i eth1 -p udp --dport 1194 -j ACCEPT
iptables -A INPUT -i tun+ -j ACCEPT
iptables -A FORWARD -i tun+ -j ACCEPT
iptables -A FORWARD -i eth0 -o tun+ -j ACCEPT
iptables -A FORWARD -i eth1 -o tun+ -m state --state ESTABLISHED,RELATED -j ACCEPT