To use the VPN service provided by ItsHidden.com, complete the following steps (that were partially found in this Ubuntu forum thread):

要使用itsHidden.com提供的VPN服务，请根据下面的步骤操作：

  1. Install the PPTP plug-in for Network Manager//安装nm的PPTP插件 $ sudo apt-get install network-manager-pptp
  2. Restart Network Manager//重启NM服务 $ sudo killall NetworkManager $ sudo NetworkManager &
  3. Create the VPN connection //创建VPN链接
  4. In the “Advanced…” settings, enable “Use Point-to-Point encryption (MPPE)”//在VPN创建窗口，点击“高级”，勾选“使用点对点加密”

附图如下：