> ## Knowledge Base Index
> Fetch the complete knowledge base index at: https://help.courses-plus.com/sitemap.xml
> Use this file to discover available pages before exploring further.
> Pure-Markdown content can be obtained by appending a '.md' suffix to the content URLs listed in the sitemap (without the trailing slash).

# Must see (timer) lessons

In Courses Plus lesson editor you can mark the lesson as "Must see" and set a minimal time required to pass this lesson. 

![Timed lesson in Courses Plus app for Shopify](https://storage.crisp.chat/users/helpdesk/website/3aea62344d5c9200/screenshot-2024-01-31-at-11224_1gwcwjq.png)

With this setting students will not be able to mark the lesson as completed before the time you specified has passed. 

![Timer lesson settings in Courses Plus app for Shopify](https://storage.crisp.chat/users/helpdesk/website/3aea62344d5c9200/screenshot-2024-01-31-at-11235_y3p89n.png)

Students will see this kind of a lesson like this:

![Timer lesson in Courses Plus app for Shopify](https://storage.crisp.chat/users/helpdesk/website/3aea62344d5c9200/screenshot-2024-01-31-at-11293_1ybia0b.png)

While timer is running, it is not possible to check (mark) the lesson as completed. This helps to make sure that your students spend some time on a lesson and read its contents rather than just mark it as completed.