Long press your song on the library screen to select it, tap "Copy Song" at the top of the screen to create a new song. Go to the Files tab, tap the page order field, and only add the pages you want to use from the PDF. Then you can use this copy of the song in your setlist. That would be my recommendation. Skip's suggestion to use the Create Snippet feature also works, as it effectively does the exact same thing.
Mike
Mike