The meetings tool is an add-in which works in the background of Outlook to gather meeting data from your calendar and present an analysis back to you.
All versions of Outlook from Outlook 2007 enable the full functionality of the add-in. To understand which version of Outlook you are using, please take a look at the Microsoft guidance on this. Then please select the installation guide you need below. Each installation guide has a link to the correct version of the add-in. Please follow the guidance carefully.