A TI-Nspire file that holds problems and pages is a document. You can manage your TI-Nspire documents with these shortcuts or use them to access the Document and Context menus:
Access the Documents menu: Doc
Access the Context menu (right-click): Ctrl-Menu
Open Document: Ctrl-O
Close Document: Ctrl-W
Create New Document: Ctrl-N
Insert New Page: Ctrl-I
Select Application: Ctrl-K
Save Current Document: Ctrl-S