If scanning then uploading, the pages will be in random order. It is best to create a PDF that can include story and pictures.
You can scan the pages and upload them under Memories. You can also write details about the book in the "Memories" tab. For example, what the book looks like, who has a copy, etc.
as Nida said - scan them to PDF first - and then you can upload to Memories.
probably best to do pdf batches in like sizes of 25 pages each at the most
(there is a 15MB file size cap you have to stay under)