On the Portable Speaker/PA system, look for the section that includes the word "OUT." The section may be called "AUDIO OUT", "TAPE OUT", "PRE-OUT", or something else with the word "OUT." It is typically an RCA connection (red & white cables). Use the RCA to Auxiliary cable to connect this section on your PA system to the "AUX. AUDIO IN" input on the Eversound Transmitter.