If your section have more then one part, then you create article tag and inside that, create many sections as you need. For example inside article we need two section for right and left navigation bars. Or for sign in and sign out parts. I hope this will help you. Im new here too
Of course. For example, if you wanna just use names you use one section tag and put your names inside it, but if you wanna use more informations like last name age sex phone numbers and ... Then you create one article tag then for each of this items you use one section like one for name one for last name one for age.