Need help to setup plex media server

[PBAMadrid]

I´ve just bought a F2-223 Terramaster and I´d like to setup a plex media server. I have a movies shared folder with only one user as admin in the NAS. I´ve installed the plex media server app and connect to my plex account, but cannot scan my folder. There´s no activity when I try to scan the library.
In the apps section of the NAS I´ve read something like I should grant permissions in the media user group, but I have no idea what it is (this is my first NAS and I don´t know how permissions work...).
Sorry if my problem is basic, I would be very thankful for any help on this.
Regards

[TMzethar]

User group "media" represents plex's permisisons for the files. Please go to Control Panel - User Group, edit the "media" to change the folders you want to scan as "Read/Write".

[PBAMadrid]

Solved! Thank you so much for your help. Just one additional question, I changed permissions to "read only" and it works perfect. Should I change them to Read/write?

[TMwuu]

{L_BUTTON_AT}PBAMadrid

Set to "read only" permission is OK, of course, you can set to "read/write".

[PBAMadrid]

Thank you!