Sounds like you did everything right. I just looked at this programme yesterday and it’s pretty basic – not sure why you’re not getting an audible recordinng. Does the microphone work in other cases/applications? Is the volume high enough?

I’m not certain but you could look to see in the microphone settings accessible from the sound recorder itself – it’s a button that takes you to a part of Windows settings, I believe, to configure which apps are permitted to use the mic. Mine worked right away though without being granted permission – I think all windows programmes may have it by default.