If you’re curious about anything related to courses on your Moodle site (I can’t imagine that you aren’t curious about courses as they are the focal point of all that is Moodle) then the Courses docs at Moodle.org are a great resource for your and other Moodlers. From course settings to formats to meta and more, the courses doc covers a lot of information. Start here and then explore to the various sections: http://docs.moodle.org/24/en/Courses. The course formats page is my favorite http://docs.moodle.org/24/en/Course_formats to browse.
What do you wish you knew about courses before starting with Moodle?