Hi Fanny,
First is to make sure the OS recognized the input devices. If on Windows, check that your devices show up in "Sound settings" in control panel.
If MATLAB was open when connecting the device, you need to use audiodevreset or restart MATLAB.
Once recognized by the OS, you can list your input devices.
audiodevreset % or restart MATLAB
adi = audiodevinfo;
adi.input.Name % list of input device names
