When I was in college (…and that was a while ago) this subject was part of a course that all accounting students had to take. But that is not the case today.
But I think it will help if I first explain what it is not! It is not the traditional balance sheet and income statements with footnotes, etc. Those are referred to as external financial reporting. That is, reporting to banks, government units, and shareholders who are not involved in the routine managing and running of the business. In those external financial statements expenses are grouped by what accountants call “function”—for example: cost of goods sold, gross profit, selling , administrative, overhead, other, income taxes, and net income.
But as a manager and/or owner of a closely held business, you know this: you want to have enough sales, in units and dollars, to cover all of your variable costs (those that vary with sales), all of your fixed costs, and generate a profit for you!