How to install openvpn on Lubuntu?

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http://askubuntu.com – I went the the connection manager, then clicked on the VPN tab, but the add button is disabled. What should I do? I cannot connected to the internet without the VPN turned on. I'm trying to install openvpn as a client. I already have the ca.crt and the client.conf with me and currently connected thanks to windows xp. (HowTos)