To: rcpwisc
Hello,
Thank you for the screenshot. That seems, that you have no any connected device.
Please, in the Record Settings windoe, please choose Show Disabled Devices (see 1.jpg)
In case when new devices appear in the list, make them Enable (see 2.jpg)
If everything is OK, that will be similar to 3.jpg
After that, please try to repeat the procedure, choosing Stereo mix etc...
Best Regards