New to management

Just got promoted to head of department 3 months ago.at first I thought it was easy. You know, just ask your staff to do the work. But I guess my perspective was dead wrong.

I have to deal with a lot of people, inside and outside the organization. Not that I can’t handle it, but it takes a toll on what I plan to do.

Anyone out there can give an insight on how to be at least an effective lrader if not a good one? Cause I sure need some kind of guidance here.