For each column, subtract your net expenses from your net income for the week or month. This gives you positive cash flow (you receive more money than you spend) or negative received cash (you spend more than you receive).
You can then maintain current weekly or monthly totals to get an idea of your estimated cash flow over time. Too many negative weeks can cause problems, and you need to plan to ensure you can meet your commitments – e.g., Payroll payments, loan payments, and rent. Also, a few positive months can mean you have money to develop or invest.