Help i cant see the folders

[tom80H]

Probably an issue on how you mounted that drive and/or how permissions are set.
Have a look at this post from the tips & tricks section for Linux:

Linux Tips

Using other hard drives (Windows or Linux) with PMS This How-To is written to help with Internal and External drives. It also is written to demonstrate how to cope with NTFS and EXT4 formatted drives. By logical extension, any format supported by Linux can be handled using the technique shown here. In all cases, the goal is to give user plex permission to read your media files which Linux doesn’t allow by default due to its strict security model. We will walk through the steps needed …

Edit: alternatively… if you’re not familiar with Linux… you might consider moving your server to a platform you’re more comfortable with (e.g. Windows, Mac or a NAS that’s taking away some of the complexity for you)

Edit/PS:
just to confirm I didn’t misunderstand… you have your Plex Media Server installed on the Raspberry PI. The media is on 2 external HDDS connected to that Pi.
On re-reading your post I’ve stumbled about what role Windows 10 plays in that setup – my 1st interpretation was you’re accessing the Plex Media Server from another device in your home network running Windows 10 – is that interpretation correct or do you indeed have a 2nd Plex Media Server (not you have me confused )