If you want to stop the Search Indexing of your school, you will need to navigate to Site Builder → Custom Code and add the code under <head> logged in (html) and under <head> logged out (html).:
<meta name="robots" content="noindex,nofollow">
Click on Update and then Save your changes.
Note: You will need to remove this code from the Custom Code section before you are ready to launch.
Exclude from Sitemap for specific pages
You can exclude selected pages from being indexed under the SEO properties of the page. This is useful for individual pages, while for the entire school adding the code mentioned above is way faster.
In the Site Builder hover over Page and click on Page SEO:
Scroll down, select the Exclude from sitemap option, and click Save:
Note: Regarding your courses, you can turn them to Draft, Private, or Coming Soon from the Access Tab of each course as is explained in our respective article.