Investing – when you have incomes or outflows of cash from activities connected with non-current assets (property, pland and equipment; intangible assets; investments in other entities etc). If you purchase or sale something from this, you put cash flows in investing activities. Also if you receive dividends from your investments in other entities, you put that dividends here.
Financing acitives connected with your share capital (issue of shares), loan notes (repayment or purchasing more during the period), paying dividends to your shareholders. If you receive or spend money for such activities, you put such cash flows in financing activities.