The second LNB output is for a second receiver if you have one, the small cable is designed for through window connection, if you have sash windows and don't want to drill the wall or window frame, this will run underneath the bottom of the window, otherwise don't use it.
PS. If you connect the scart lead to the output labelled TV and then connect to your TV, switching on the box should bring up a no signal message, pressing the menu button should bring up the menu. If you have no picture, press the TV/SAT button on the top of the remote.