This document provides an introduction to key financial planning concepts for entrepreneurs through the example of budgeting for a holiday cottage business. It defines important terms like establishing budget, operating budget, turnover, variable costs, contribution margin, contribution margin ratio, fixed costs, depreciation, and net profit. The example operating budget calculates that the holiday cottage business could earn a net profit of 22,000 Danish kroner per year based on assumptions for revenue, variable costs, fixed costs, depreciation, and interest payments.