I need to figure out how to use a keyboard with a USB port

First of all, thank you for opening my post. I’ve had a very frustrating time with this. I love audacity and have been recording with it for years. I ussually just set the mic. atop the keyboard and record, but I recently got a USB port. I know it will be far better quality if I use the USB port, but although it’s all hooked up, I don’t know how to get audacity to record. Please help!

Sorry, I don’t understand. Do you mean that you now have a USB microphone, or a USB keyboard?

It’s a USB cord, which is hooked up to my keyboard.

A USB cord?
No, sorry, I still don’t understand - what make and model is it? What does it do?