How do I program in an interactive journal?

I am working on a big 3D game project. One of our main game mechanics is the use of an interactive journal. This journal will serve as the main menu (cover), pause menu, allow the player to save and load their progress, keep a log of their progress, allow them to access the camera and photos taken with the camera, access collected items, and write/type notes. It would also have to be able to have its pages turned via animation.

This is a big mechanic. I only have a basic understanding of Unity. Therefore, I was hoping to get some advice, resources, or help with getting started and understanding what is needed to accomplish this.

Thanks for your help!