Open The Ubuntu Software Centre and ‘mouse’ over the top panel to reveal the Application Menu. In the ‘Edit’ menu select ‘Software Sources’.
A small pop-up will appear asking you to enter your password to ensure changes being made have your approval. Once entered click ‘Ok’.
Another window, pictured below, will open. Along the top of the window are a row of tabs. Click on the second tab, named ‘Other Software’, followed by the ‘Add’ button located towards the bottom
Another small window will open. Its here you copy and paste the follwing line :-