The Track page has a few sections:
Invite Tracking and Details - You can view the total allocations, number of invites sent, number of invites drafted and the number of invites remaining for all of the groups in your event.
Element Tracking - You can view all of the elements in your event and the number that have been Accepted, Pending and Remaining. The Tracking column lets you know how close to your inventory limit you are (if you set one). The elements with the infinity sign all the way to the right means that no limit was set.
RSVP Tracking - This calculates all RSVPs for the event. If you hover over each section the number of RSVPs for that section will pop up.