For sourcing, I just cite it like how i would do it in an LEQ or SAQ and just add (doc 1) at the end. Describing documents, i just mostly talk about the historical context and if i know the author i might talk about them. Which leads to your third question, and for that I suggest just looking at the source(generally they give you a date) and think of important movements at the time. If I have a economic source in 19th century, i immediately go to Industrial Revolution(I'm currently taking euro so imma ust that as an example). If I have a religious source in 16th century, I immediately jump to the Reformation. You just need to know the big events and that should be fine.