get on top of (something)
To get complete control of something; to become fully informed or up-to-date about something. A: "How is the new project going?" B: "Right on track! Jen got on top of it while you were on vacation." I don't know how you get on top of all the different student issues that are brought to your attention.
be/get on ˈtop of something
be able to manage and control problems and difficulties successfully: I’ve finally got on top of my new job but it took a long time.