With the help of this dialog you can rebuild PDF document, i.e. change page order, remove some pages etc.
You can add, edit and remove page ranges, which will be in the output PDF document.
Use corresponding buttons to set the order, in which specified page ranges (or separate pages) will appear in the output document.
You can modify input document (select 'Overwrite existing') or you can create new document (select 'Create new'). If you want to work with this dialog after you have applied changes, uncheck 'Close after operation' check box.