Locking the course

Hi,

I have a huge course that needs to be "locked" and users can only move forward if they have viewed the slides. In Storyline, I would typically use the "When timeline ends" to ensure that. I am working on a coworkers file in Studio and I am not too familiar with the process on this system. I have tried locking the screens in the presentation options- but now I am unable to move forward at all. Am I missing something?

This specific course is huge (431 slides total) and I want to avoid having to manually unlock all of the screens.

Any suggestions?

Thank you,

Nicole