No need to apologize, we all start off in that state :)

The Arc (or Beam, or Amp) communicates with the TV via an HDMI-ARC cable. If you can run a CAT-6 cable to the Arc, that would be good as well. Some TV’s like to have a wired connection, you could use a simple 4 port unmanaged switch to feed both devices from a single cable.  

The surrounds, and Sub are designed to wirelessly connect to the Sonos Arc, and would use a 5 Ghz channel, no need to wire CAT-6 to their locations. 

Sonos doesn’t tend to like managed network switches, so be careful there. Multiple devices “wired” directly can cause network storms if the router isn’t set up properly, but if you just wire the single Arc, you should be fine. In general, the 5 Ghz signal from the Arc should reach the Sonos Amp 20 feet away, assuming it is powering the “rear” speakers. Wiring it with CAT-6 is OK, but shouldn’t be required, the system is originally designed for wireless connection, the wired connection is secondary.

You may want to use Google to search for STP and RSTP network storms on this site, they do happen with managed network switches, depending on the settings. I say that to warn you that the search function on this forum is sometimes fine, but often doesn’t bring up the data you’re looking for, whereas Google tends to do a better job. 

I don’t recall a single, particular thread that is set up for general questions along these lines, but there have been lots of individual threads with people who have run ini to difficulty. 

As an aside, if I was working in the walls these days, I’d make sure to have an optical as part of the structured wiring solution I’d be installing, for future proofing. Not sure it would be necessary yet, but would rather install it than rip open the walls in a year or five for another run. 

Managed switches are not an issue if they are managed properly. Unfortunately. the default settings are not always appropriate for SONOS.

Yes, be sure to run some fiber because copper is running out of bandwidth.