In order to see what a user is working on in real time you can go to Home → Dashboard → Active timers. That way you can see what a user is currently tracking.
If you can't see Active timers on your Dashboard, you need to click on your name (bottom left) → Apps and enable it from there.
Admins will see the timers of the entire company, project managers of the users they manage, while a regular user will only see his own timer.