Unless you publish your mock test, your learners won't be able to see and take the mock tests. So once you create your mock test, next thing you need to do is publish your mock test
Got to your admin dashboard. Click on Mock Test and go to any mock test that you want to add FAQ to and click on settings or while creating the mock test click on settings
Alternatively, you can click on Publish button from Quiz builder page directly
In the next page, review your final quiz configuration and click on Publish This Quiz
Now your mock test will be live and your learners can take the mock test.