When Atomic Search is installed, the default configuration allows students to search their courses. To prevent students from searching in a given course:
Click on the course, then on Search within the course navigation menu.
Navigate to the three-dot button at the top right of the page.
Toggle “Allow students to search this course”.
To have these changes take effect immediately, select Reindex Course in the three-dot menu.
If you disable "Allow students to search this course," once the index is updated the course will no longer show up in students' search results.