Allow your students to try some of the lessons for free with the Trial Courses feature.
To enable Trial courses go to the STM LMS > Addons and enable it.
Click on the Shareware menu, that will appear on the dashboard after enabling the addon and enter the number of free lessons you want to be in the course, Save Settings.
Now, when you create a new or edit an existed course (see this article to learn how to add and edit Courses) in the Course Settings section under the Settings tab enable Trial Course feature by dragging the slider to the right.
Saved settings (number of free lessons) will be applied automatically to the course. Students will be able to complete free lessons on the trial course without purchasing. The rest of the content will be accessible only after they buy the course.
Once the free trial lesson is completed, a student will be offered to buy the course to unlock the rest of the content.