Open your course's reading list and click on "New Section":
In the New Section menu you can add the section's title, description, and, if you wish, a start and end date for the section. This is useful if you want only the current week's readings to be visible to students. You can do this by checking "Section visibile only during these dates" checkbox. If left unchecked the section will be visible to students throughout the semester:
Next, click 'Create.' The section is now added to your reading list. You're ready to move or add resources to the new section.
Watch a video from Leganto demonstrating this procedure: