Can you have multiple accounts on plex

Hello, can someone help me please. I have a WD My Cloud Home Duo, I have 3 users attached to the device. For myself I have Plex set up and it works fine. With my wife she has enabled Plex and gets the Plex folder but that’s as far as it goes. How does she get Plex to scan and recognise her library.

My question is can she have her own library using Plex to upload things for herself on My Cloud and we share access to one another’s. I’ve listed her as a friend and she can see all my media but there does not seem to be an option for her library to scan her Plex folder, on the Plex website her library doesn’t exist.