Connect microphone to RN-52 Bluetooth module
The datasheet contains microphone connection for regular electret microphone (middle of the schematics on p.13 -- this involves 2k2 bias resistor to MIC_BIAS, and input on MIC_L-/MIC_R- via 47nF capacitor). 

However in your case, the microphone already contains amplifier. So I advice connecting microphone in non-differential way: MIC_L- goes to ground, MIC_L+ goes to microphone output via small capacitor (any value of 47nF or more will work). 
Make sure to use 'lime mode' and not 'microphone mode' in your setup.