I am completely new to docker, please forgive any simple mistakes or silly questions 
I am setting up a media server, and am going to run different apps in separate containers (Plex, Sonarr, Transmission etc.)
I want to understand where the data for these programs is saved (e.g. config data / library metadata). I had the impression that I could create ‘snapshots’ of the containers on a time interval, and if anything went wrong I could restore a container to a slightly older version.
However I don’t fully understand the differences between ‘commiting’ and ‘saving’ and containers and volumes.
I just want an easy way to restore an app to a previous state (with all my config settings and data) if anything were to fail / the container was accidentally deleted etc.
Thanks for any help!