STM LMS > Lessons menu includes your Lessons list. You can add your Course content either with VC Page Builder or WP Classic Editor. Also, here you can add the lesson's featured image and set up publishing parameters.
The Lesson settings section allows you to choose:
Lesson Type: Text, Video or Slide;
Lesson Duration: any text;
Lesson Preview: Makes the Lesson open/private for visitors;
Lesson Frontend Description: Description of the Lesson;
Lesson video poster: you can upload a video poster or enter the video URL;
Lesson video URL: use the URL for the video lesson
Lesson materials: upload different files as lesson additional materials.