Open the system menu from the right side of the top bar. Select Wi-Fi Not Connected. The Wi-Fi section of the menu will expand. Click Wi-Fi Settings. Click the Connect to Hidden Network… button. In the window that appears, select a previously-connected hidden network using the Connection drop-down list, or New for a new one. For a new connection, type the network name and choose the type of wireless security from the Wi-Fi security drop-down list. Enter the password or other security details. Click Connect.