While searching for jobs from the Home Page, the option enables you to specify the range of your expected annual salary. Entering the minimum and the maximum annual salary expected, will show you job vacancies offering an annual salary in the range that you have specified.
The search results shown are ordered on the basis of the salary specification that you have provided. All job vacancies matching the range entered are reflected first followed by jobs which match the other criteria you have specified but not necessarily the salary range.