The commands grouped in Pages and Options -> Bundle are designed for moving between viewed pages (or page groups in multi-page mode). The operations in multi-page mode are described in Multi-page viewing.
Pages -> Next (PgDn) changes the view to the next page. Pressing of the PgDn key preceeded by entering an integer number causes the moving by the specified number of pages forward (or backwards, if the number is negative). Moving to the next page can also be acheived by pressing the Enter key.
Pages -> Next (PgUp) changes the view to the previous page. Pressing of the PgUp key preceeded by entering an integer number causes the moving by the specified number of pages backwards (or forward, if the number is negative).
Pages -> Specified changes the view to the page numbered as entered in the dialog window. The pn (or its equivalent, np) macro, preceeded with an integer number moves to the specified page directly, i.e., without the dialog (cf. Appendix PS_View macros).
Pages -> First (Home) moves to the first document page.
Pages -> Last (End) moves to the last document page.