What is managing?

Managing is what managers ought to do. But the question is 'what is managing?'.
Best to describe it as:
"enabling people to do the work in the most efficient way"

Enabling means that you need to provide means, knowledge and motivation.
people means that you need to respect employees and pay attention to them in a honest way
the work means that the result you want need to be specified and clear for you(!) and the person who works on it. Communicate your expectations and listen to the response and remarks of the person.
efficient means from the companies point of view the most efficient way, that is the best price - time - result. But take care, this doesn't mean as cheap and fast as possible only, there is also a social responsibility and commercial aspect of the company, that needs to be taken into account too.