how rescan audio devices?

I am new using this program.
Want to record sound from a revox taperecorder to my PC.
I have a usb key, with rca at the other site where my audio signal is arriving from the tape.
How can I activate the program to use this usb.
I found “rescan audio devices” in the help. But how do I have to do this?

What exactly is that? (make and model number).
Which version of Windows are you using?
Which version of Audacity? (look in “Help > About Audacity”)

That is in the “Transport” menu at the top of the Audacity window. Or, restart Audacity.

This will only work if this is a USB cable or USB audio device meant for taking audio-only signals from RCA outputs.