Procedure for WD Wireless passport pro setup for metadata

Thinking of nabbing one of these with 3tb for travelling in our motorhome. Currently run PMS on my Mac at home and watch via iPad and iPhone. So I guess you install PMS somehow on the wireless passport and then put all your media on the device and wait while the Internet downloads all the meta data to the drive. Is that how it Works? Since I already have all my movies and tv on my Mac with the metadata intact can it somehow be transferred to the device without having to re do all the metadata? Other thought is if I already have PMS on my MacBook and all the media on a drive attached to it do I lose all the metadata and access to plex if I have no internet connection? If not then I don’t even really need the wireless passport. I should be able to access it even on my iPad and iphone though I would need my MacBook to be turned on all the time to do that I guess.

@PCKid
I have one and love it. I use it on the road and I have only had one issue, had to do with a firmware update.
When you get it, you use the web UI for the drive to install Plex. The interface also gives you a way to upgrade Plex when needed. Will also need to setup your folders for Plex to use. After that you use the Plex Web interface to maintain your Plex libraries.
You will need to make your media playable for your devices as the drive is not powerful enough to trans-code. I use Plex to optimize then move over to the drive.
I would not put all your media on at once, as some have had issues with it getting bogged down when they load everything at once. I do a few movies at a time and just let it run.
The info cannot just be transferred (at least not that I know if).
The drive itself is completely self contained Plex server. I and others have used it completely offline. I would not turn on Plex Home on the drive.
I think I have answered all you questions. I think this little device is great for what it does/is supposed to do (in my opinion). I really think this is great for taking it on the road to have Plex - on a plane, in a hotel room, out in the middle of nowhere.
Only drawbacks that I have seen are - it can be slow DL’ing metadata if you load it up with a bunch at once. It cannot trans-code so all media needs to be optimized/prepped for the device you will use. Your watched status does not sync back up with your main PMS, they are two separate servers.
Feel free to ask more questions, there are a few of us that have had great success with it.

I think I’ll play around with my portable mobile router. It has a telco data card and could leave everything as is on my MacBook and the portable 2tb hard drive I have my stuff on. It’s just whether the TP-Link MiFi M7350 can handle the transcoding. I could use handbrake to redo all the files in MP4 for ipad and iPhone but if this way works I won’t need to. I did notice at the bottom of the Plex page for the WD passport they say Plex app to come. Wonder if when they release that then it can transcode. After all it is AC whereas my mobile router is only N. If my way works it would save me $449. That’s what it costs in Australia. Gotta love import duties and exchange rates.