Hand microphone, hand speaker

This was purchased personally when I was appointed as the person in charge of the district, thinking it would be necessary for disaster communication.

I have finished my duties and am now selling it as it is no longer needed and has not been used.
There is no instruction manual.
It has various functions, but I only know how to use the hand speaker.
① Switch the microphone and USB/SD selector to the MIC side.
② Turn on the switch on the hand microphone. The microphone lamp will light up.
③ Pull the trigger on the grip.
④ Adjust the microphone volume.
The above are the operating instructions.

Thank you for looking.