How to enable search functionality in my website

Could you please let me know how I have to proceed if I want to search by keywords on the following website ?

https://alice-o2-project.web.cern.ch/

Hi,

First you need to enable the Search module on your website.

Then go to Appearance and click the Settings of the CERN theme. In the Header tab check the option “Show Search link on Main menu” and save.

Now the search link will appear next to your main menu. From the search page you can search for keywords.

Thank you very much !
It was easier than I tought.