There are two methods for getting audio output from the PMP530M if using external power amplifiers.
The first method would be using the REC OUT RCA jacks on the front of the mixer. As the mixer is mono, each RCA output would carry the same signal and can be fed to an external amplifier for passive speakers. The REC OUT of the mixer is tapped before the Main volume knob, therefore you will not have overall volume control to thee power amplifiers. An additional small-format mixer can be used to alleviate that issue.
The second method would be to use the AMP INSERT of the mixer. A 1/4" TS cable will be used, which takes output of the mixer to the power amplifiers. This method is not recommended if you are already using the built-in power amplifier of the mixer, as this connection will stop signal from flowing to the built-in amplifier of the mixer. A solution for this issue would be to use an Insert Direct Out adapter. This allows the signal to flow back into the built-in amp while still feeding the signal to the external amplifier.