There is no list of courses (or path) to become a certified 'sales expert' because there's no 'sales expert' certification in ServiceNow. What's happened is you've typed 'sales expert' into the search box and it's returned a list of sales-related courses.
However, there is Certified System Administrator certification/path (as an example). See below the selection you'd make to get relevant courses for that path. You'd then click on the top result to see the full list of courses required to complete that certification:
