Double click on the button in the editor's Buttons page to edit. Set Button Mode to hold, then click Hold Functions at the top of the window. This lets you edit the behavior that happens when you hold the button.
Now, set button type to IA. Turn off all checkboxes except Momentary, which should be on. Group should be None
Click New Action, set Action Type to System, subtype to Page, then set the page number to your desired page.
Click Done, and transfer settings to your PBC
That'll do it!