You can use Gomo to lock content topics from your course’s Menu topic. If you have a course with more than one content topic, you can set display conditions on the Menu Buttons so that only the 1st topic can be accessed until it is fully complete. Once the 1st topic is complete the 2nd topic will be made available.
This is achieved by creating two versions of the Menu Buttons (active & inactive) and assigning them different display conditions. Only one set of Menu Buttons will have links to topics and these will only become active once previous topics have been completed.
When you save and preview the course, the Menu topic format should look like the screenshot below. If you were to select the buttons for either Content Topic 2 or 3 they wouldn’t take the Learner to those topics. Once the Learner completes Content Topic 1 the Content Topic 2 button will become active. Once they complete Content Topic 2 the Content Topic 3 button will become active.