Course sections
Using the course settings, you can arrange your course by weeks or topics.
Choosing weeks will automatically fill in the dates, starting with whatever date you specify as your first day for the course, and incrementing each week by seven days thereafter. So if you start your course on Wednesday, each week will run from Wednesday to Tuesday. You may wish to start the week on Sunday or Monday prior to the actual first day of class, so that weeks will reflect the actual work/study week of your lesson (if applicable).
Arranging by topics lends itself to rolling enrollment, or courses whose duration changes often, or where sequence is less important (though these are only suggestions). Often teachers will think about their course in terms of "modules" so topics work well - one topic per module.
Note that sections can be easily hidden using the eyeball icon. There is a course setting that specifies whether or not these hidden sections are entirely invisible to student/participants, or just show as a horizontal block that says it is unavailable. Such sections will always be full available (greyed out though) to teacher/administrators of the course.
A small hack: If you want to have a super-short course that is JUST the top with no section blocks, note that you must have at least one section. The solution is to have one, then make it invisible, and in your settings full hide hidden blocks. Now you have a "one main area" course.