Would like to be able to view and use my Tablet and mp3 Sansa with Multi Commander.
USB external drives are not listed.
They are are connected to Windows as stores devices with full filesystem access windows provides a drive letter for them and you access them as normal drives
If they are not storage devices Windows might allows access them as a Windows Portable Devices and you then find the device under WPD in MC.
Look in the device dropdown under "Portable (WPD:)"