First, check that the mic isn't muted, then use Settings to confirm permissions and reboot your computer This article explains how to get the microphone on your HP laptop working again.
They're even still worth investing in if you're already using a laptop or webcam with a built-in mic, as the quality offered by a standalone mic is almost always going to be superior. That said ...
You can record the audio via the desktop or tablet as the microphone is said to be compatible with iPad, iPod touch, iPhone, Mac or Windows PC. You should be able to digitally control the preamp ...