Typically a section is a collection of short videos on a similar topic within your course. There are no rules, but I find it better to record individual videos of about 5 minutes apiece one at a time. That way you are more likely to ensure each video stands on its own, teaching one specific thing. Many learners just consume individual videos out of context, so it is best make sure each one stands on its own if that makes sense.
Some would even say 5 minutes is too long for modern attention spans.
