Associations - shows the structures which are associated with the view (have this view in their Views drop-down). See Associating Views with Structures.
Advanced - shows additional technical information about the view.
The tabs and the scope of functionality available may be limited, depending on your access level to the view.
Renaming a View and Changing Other Properties
When you change a view's name, description, sharing permissions or anything on the Advanced tab, the changes are not saved until you click the Save Changes button. After you have saved the changes, they take effect for you and anyone else who has access to the view.
The Associations tab is different – it contains only links to structures. The associations between structures and views are managed by the structure administrator on the Manage Structure page.