How do I connect the attachments to the tube? ?

I have just acquired a second-hand Hoover Dustmanager 2000 watts...The question might seem silly, but I cannot work out how to fit the attachments...I got this from someone who has bought a new one and I wonder if some coupling device is missing...Could that be the answer? It would help if I could see a website with a few pictures...I don't have the handbook, otherwise I would not be asking this "ridiculous" question. Can anyone help?