I'm interested in how we construct and justify worldviews from a philosophical perspective.
To that end I'd like to know about how people in the Medieval period viewed the world to contrast it with more contemporary worldviews.
Due to the lack of sources about what the common people thought I'd like to focus on someone about whom more sources are available. (Like frederick II)
How should I best approach this?
I've completed a course on Medieval philosophy so I'm already a bit familiar with what major intellectuals thought at the time but I'm not trained in historical research.
I'm not sure what you mean with the qualifier 'as a lay person'?
Nonetheless, this well-measured biography is still considered the best starting point in English:
This will give you, inline and in footnotes, more than you could ever need to pursue your idea. That said, Frederick was a pretty incredible person and unique in many ways.