dashboard
All data on that page will be refreshed automatically every few seconds.
Each point on the chart represents a scan (X axis) and the amount of issues that scan logged (Y axis).
The Notifications section list actions taken against items which concern you by either being owned by you or shared with you.
Unread notifications are highlighted in pale blue and a widget appears on the top right corner of the navigation menu that allows you to briefly review them from any page of the interface.
The Activities list shows your own actions. Users with which you've shared the items appearing on that list will see these items in their Notifications.