This is basic information.....
....every boater should know. The Coast Guard will cite you for not having the proper identification lights and/or not using them correctly. More importantly you pose a danger to yourself and others. Please take the time to look at a basic boating book or any of the free Coast Guard publications concerning boating safety.The top/masthead light is visible for 360 deg and has its own circuit because that is your ANCHOR light. The light halfway down the mast is usually called the MAST light, also on it's own circuit, and is used to indentify a boat running under power (motor on). The white light on the transom is called the stern light. It is visible 120 deg aft, and, with the red and green bow lights on the same circuit, comprise the RUNNING lights. I leave it to you to learn their proper usage. good luck.