Once a Page Library has been created, it's ready for you to add documents into it.
Add a document to a Page Library
Select 'Manage' for the document from your homepage.
Select 'Manage Version', followed by 'Version Settings'.
Choose which Page Library you would like to add it to from the 'Part of Page Library' drop-down list.
The documents can be amended at any time too, which will update the library!
Read the Page Libraries Guide - https://view.pagetiger.com/TigerLabs/page-libraries