How do I switch from Wi-Fi to Ethernet cables?

If you have cable throughout your house you could run an MOCA ethernet to coax adapter. Had a similar situation of modem on one floor and streamer on another. I had coax running through home so installed MOCA ethernet adapters on each end of coax. Works well.

https://worldwidesupply.net/blog/moca-adapters-beginners-guide/

The OP @imaninatural mentioned a desire to move from wifi to wired. It was not stated what his/her reasons are. Is it in the hope of better audio quality? Or is it because the wifi has hiccups?

Hiccups can probably be mended with a wifi extender or a wifi-mesh setup.

I would not put my hopes up for improved sound quality if there already is enough bandwidth for lossless streams. They will reach your Bluesound Node without error, otherwise your Bluesound would not be able to update it's firmware without error.

I use the TP Link Power Line adapters and they work great .  From the TP Link  AC adapter I run ethernet cable to a TP Link switch.  The switch has two SFP fiber optic ports.   I use a fiber optic media converter for my Vault and another one to my Aurender N200.   Works great, quiet, you would never know i am running an ethernet over AC adapter.

Anyone use two Apple AirPort AirPort Extremes as a WiFi mesh setup? One hardwired to the router & communicating with a second in their audio room? That's what I use with quality cat 8 cable. Wondering what, if any, the limitations are in this type of mesh network?

So many people commenting, so few facts and so little knowledge, really sad.

First, Wi-Fi is wireless Ethernet. So the medium changes. But the same protocol.

Second, properly designed Wi-Fi can support almost all applications, outside multi-gigabit transfers and systems they use. 

Third, Cat8 cables are made for 10G and above, and so far no consumer grade streamer supports those speeds.

Fourth, a fundamental concept of Ethernet is that as long there is stable connection, your data is transferred 100%. 
 

Fifth, streaming from Qobuz, Tidal, and others are actually not streaming, they are download at maximum available speed, and then that song is stored in a cache for future playback. This fact alone 100% invalidates any and all “Ethernet upgrades”.