You have two main way to access your WD mycloud NAS:
enable and cnofigure the embedded twonky DLNA server in your NAS. You will then be able to access it via the stock Video app (it will be shown in the device section) as well any other addition player (Kodi, VLC, Archos)
some additional player (i use Archos player, but at least Kodi too can do it) can access directly network file systems shared via SAMBA protocol. In Archos you simply go to the network section and your NAS will be shown even if it is not DLNA enable. BTW with this protocol Archos is able to add all the metadata to the video
I have a My Cloud NAS working with my KD-43X8309C.
i can't recall any steps other than just running the red Video app under Apps (not the Google Play one), finding the WDMyCloud under Devices there, and drilling down to the videos on it.
There's no music on my MyCloud, though I imagine it would be the same thing in the purple Music app.
YouView Superuser, but not an employee of YouView, nor retained by them for this purpose. It's purely me speaking
