[Zubersoft]

Normally, you should only have to tap Import->Local File, select the PDF, enter the collection on the import settings dialog and any song created during the import would be assigned to that collection. If you are using Import->PDF Bookmarks, you would instead check the option at the bottom that says, "Edit songs after import", then on the batch edit screen, just enter in the collection you want to assign to all of the new songs that were created.

Mike