Is the boom mic recording audio?
The boom mic is a sensor. It converts audio into an electrical signal. To record that signal you need a recorder of some kind, one that is capable of amplifying a microphone level signal and recording it. Usually that means a digital recording device, which could include something like a Zoom recorder, a camera with an external mic input, a phone with a mic input, or a PC with a mic input.



The type of device depends on your needs and budget. The recorder you have is the the best recorder, so if you don't want to spend money you could investigate whether you can plug an external mic into whatever equipment you have at hand. 

Depending on your microphone you may need an adapter to change the plug into the plug on the device. Professional microphones almost all have a three-pin connection called an XLR connector (pictured below on the right), consumer grade mics usually have a mini-jack connector (below left). So if you have the former on your microphone, but the latter on your recorder (e.g. the Zoom H1n pictured above only has a mini-jack input), you'll need something like this: