You can add a Sonos Bridge to an S1 system only.

What was the reason for purchasing the Bridge?

Limited access to router and ethernet ports. Router is the basement.  I have jury rigged a system with 4 play 3 speakers.  I was hoping the bridge could be put near the router but I don't want to mess up what is currently working.

You are better leaving your system as is, rather than adding a Bridge.

Sonos themselves do not recommend using the Bridge.

“If you have Sonos Bridge wired to your router, we recommend removing it from your system“

If you really wanted to move to a wired setup, then you could purchase a 2nd hand Sonos Boost and connect that to your router.

Or just run an Ethernet cable directly to a SonosNet capable speaker. Most ‘newer’ Sonos devices are not capable of using SonosNet. Although they also can’t run S1, either. 

Bridge, as said is a horrible idea.

The much newer Boost is better but still obsolete.

The preferred connection would be all your Play 3s connected by Wi-Fi only.

Wiring one or more Play 3s would move you to SonosNet for ALL SonosNet capable Sonos devices. I found that less robust than the WiFi option here.

Yes, you can add a Bridge to your existing system it’s actually a great idea if you're looking to improve stability and range, especially in a Sonos setup.

Just plug the Bridge into your router via Ethernet, open the Sonos app, and follow the prompts to add it to your system. It will create a dedicated wireless network (SonosNet) for your speakers, which helps reduce dropouts if your Wi-Fi is spotty.

However, do note that Sonos has phased out the Bridge in favor of the Boost, which offers better performance. If your Bridge works fine, great just know it's older tech.

Moderator Note - This is most likely AI, we don’t recommend using the Bridge