How should a "brief synopses of each paper" look like?
This is a fairly simple assignment. To answer your questions:


Obviously your name and class information should appear at the top of the assignment (unless otherwise instructed by the professor).
The "title and authors" referred to by the professor are in reference to the paper that you are discussing, not you!
You are told to write in complete paragraphs. That means no bullet lists, so write everything as complete, well-structured sentences. 
Spacing and font are up to you, but in general, I'd use at least 1.5 times normal spacing and 11 pt or larger font (unless you're working with LaTeX, in which case the formatting is handled for you).