I need to know how this website works

 Hi all,
 look at this website please i want to do like this http://eng.iugaza.edu.ps/en/Default.aspx, i need to know how he databind the Menu from Database
For example when you go to Departments in the Menu Then Civil engineering you see the Dep_id in the query string
and when you click on the civil engineering and go to the other page you see Vertical menu,when you hover on Introduction in the
vertical menu you see another query string Page_id
how this website works?i mean what exists in the table page and table department?
please help me
i need it necessary
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