If the demo plugin does not work – something during your installation went wrong. If you use a current sd-card-image (e.g. Max2Play version 2.22) and follow the points I wrote above, it should work (just tested it again to make sure it really does).
IMPORTANT: as this is still in BETA-Mode you MUST update Max2Play to the current Beta before doing the update on Kodi (click on Beta Update on Settings Page!).