I suggest you start with using Sonos via openhab by creating the things, linking the needed channels (playURI amongst others) to items and using them via an UI.
If you mastered that ( playing song) you can start using a rule.
The time-based start is made using a “cron” statement, search the Documents and forum for examples of cron as well as for the playURI examples.
That’s a good suggestion because I can’t figure out how to even play a song. What type of item would allow me to navigate to my library and choose the track? I can display it on my control page in Paper UI but the only thing I can do is click play.