How do you want to organize your course content?
One of the first tasks in designing your course is to select a course format. This sets how your course is organized.
The format you use depends on the theme you choose. Not all formats and themes work well together.
Steps in Snap: Course Tools > Edit course settings > Course format > Format
Steps in other themes: Course administration block > Edit settings > Course format > Format
More on Course Formats on the Moodle website (may be available in English only).