NoteShelf 3 - Taking notes next to PDFs

I just downloaded Noteshelf 3 after reading about different note taking apps for my S9 Ultra tablet.

I uploaded a PDF into a new notebook but there isnt enough room to take hand written notes in the margins.

Ideally I want to be able to upload Textbook PDFs and PPTs (as PDFs if needed) and then have them a bit smaller so I have room to take notes in the margins or on the side.

Does anyone know of how to do that in Noteshelf 3 or is there another app that does this well?