In order to see what a user is working on in real time (if they're using any of the time tracking tools), you can:
1. Go to Home → Dashboard → Active timers. That way you can see what a user is currently tracking.
NOTE: 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.
2. Go to Timesheets → Toggle the Active timers view (top left corner).
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.