The red aircraft beacon is usually mounted on the vertical fin (Cessna and Murphy types) and switched on to indicate a 'live' aircraft, i.e. with the engine about to start or already running.
On this page we show you the mounting kit of the Kuntzleman Electronics, Inc.
LED Beacon mounting kit from KEstrobes
The document shows all parts of the kit and the correct way of installing it in your aircraft.
Experimental Aircraft Info