Deleted permissions - how do I restore them

Server Version#:DSM 7.3.2
Player Version#:
I was wondering why my Synology Disks kept spinning when there was no activity. I went onto my Windows PC and I looked at the permissions in File Explorer to see the folders where I keep my music and pictures. I saw under the security tab that certain “users” had read-write access. I am the only user of this PC. So I removed this for the folders and in doing so I broke Plex Media server, Plex for my car and Plexamp for my phone iPad etc. Any ideas on how I restore this or do I have to reinstall Plex?

Make sure to manage file permissions on the Syno itself (not using Windows file explorer!!).