General Photoshop Resources:

https://helpx.adobe.com/photoshop/tutorials.html

Creating PDF Presentations

https://helpx.adobe.com/photoshop/using/contact-sheet-pdf-presentation-cs6.html

About Photoshop PDF Format

https://helpx.adobe.com/photoshop/using/saving-pdf-files.html

VIA Acrobat

https://acrobatusers.com/tutorials/how-to-create-a-presentation-or-multi-page-pdf-from-photoshop-cc