Enable course preview before enrollment

In a course, few selective lessons/tests/surveys can be set as preview-able without enrollment, It allows learners to preview some content before enrolling in the course session (buying full course from catalog). Catalog list page shows a preview button for the courses those are set as preview-able and user can access preview-able lessons before enrollment. Preview can be enabled on individual course basis. 

Site Security Settings -

If you want to allow preview course option to anonymous user ( non registered user), you should disable site level security setting -'Require Signin (All users must signin to access the microsite)' .

Course Setup

Preview by All users

To allow Preview for a course by all users, select Preview-able by all site users checkbox. (Course should be authorized to everyone, rather than specific groups).

Preview by users of selected groups

If you want the Preview to be limited to users of specific groups, then use the Members of Selected groups radio button, and also check "Also make it Preview-able". Then add the authorized groups for the course using the +Add Groups button. 

Lessons settings

Besides setting the course properties, you would also need to enable Previewable property of the lesson. 

Previewable Tests/Surveys

To have previewable tests and/or survey, enable the it's Previewable settings.

Course Catalog Listing 

For courses that allow preview, a preview button appears along with Buy button.

 Course View

When you launch the course in Preview mode, you can only access previewable lessons, tests and surveys. Other content will be locked in the course outline. 

Message on Non-Preview-able Lessons

When a user clicks a non-previewable lessons a message appears to check enrollment options, clicking the button brings course sessions link to enroll in the course. 

Check Enrollment Options brings available course session's link that takes user to enrollment/payment page.