First, you start with the income statement. Revenue-COGS-Operating expense-Depreciation&A-Interest Expense-Unusual expense=Net income. Second, the net income is added to your Shareholder's equity. Then you have to tweak the balance sheet in accordance to the changes in asset and liabilities sides. Last, now you can build the cash flow statement using Income statement and Balance sheet. CF from Operations, CF from Investing and CF from Financing activities.