Where/how does the WP website hold the data?

With regard to the data (digital images and some transcriptions) of the website I would like to create, is there a tutorial to explain where the site will access data from? Is there something called “data items”? In other words, where does WordPress pull the data from, if one does not wish to create a post or a page? Where must a place my digital images and transcriptions and how do I do this?

My previous experience with WordPress is in the world of blogging and I have no experience of programming, therefore I don’t know how to adjust WP to hold content and pull it when needed.