Once you have added a section you can add lessons under that section. To add lessons to your sections click on desired Lesson type button or drag and drop the Lesson button into the dotted area
Click on Section Quiz

In the next screen, you will be asked to choose a template to start creating the section quiz

Once you select the template click on create and you can create the sectional quizzes just like your mock tests. To know how to create the questions, please click here