Permissions restriction by user for Files shared?

I’ve setup a NAS with a Zimaboard 832 and a USB 3.0 hardware RAID as the storage. I would like to be able to provide private folders to different users in my household so that they can access their files but say their sibling cannot (pre-teens).
This doesn’t seem like an option with Files sharing.
Is there something I’m missing? Or is there an alternate recommended solution to do this (I don’t want to install a dedicated NAS OS as the goal for the Zimaboard is also to have it perform a few other functions.
Any help or guidance would be greatly appreciated.