Plans are a great way for teachers to prepare a course roadmap with structure, scope and sequence, and it can be customized based on the teacher's needs. For example, blocks of information may be set so that only the teacher may view the information.
It is recommended that you build your course through Plans.
But before you start, read this PDF link.
Keep in mind that Plans can be customized to meet your instructional needs. The above sample is from a relatively traditional teaching format.
Also note that from the calendar - on the Plans tab - a student or teacher can see all their current plans from all their courses. This makes it easier for them to see what they have to do without having to go into the different courses.