home cinema set up

No, the Beam would be connecting to the signal from the BOOST, the surrounds would connect to a hidden 5Ghz signal generated by the Beam (not part of SonosNet). But that’s just network topology that I don’t think you need to worry about. Set up your Beam and surrounds following the prompts in the controller, and you’ll be fine. 

Reading this it says one of your speakers has to be wired to the router( boost) I think my beam would have to be connected to the boost to have its own Sonos WiFi network 

https://support.sonos.com/en-us/article/choose-between-a-wireless-and-wired-sonos-setup

Home theater

Sonos products that are used as home theater surrounds or subwoofers are unable to act as the first-wired product for the dedicated Sonos wireless network.

You only need wire your Boost to the router - if someone did not have a Boost, then they can use a Speaker in its place such as a Sonos One, Five etc. The wired device (if it is a speaker in place of a Boost) should not be a Home Theatre Surround, or Sub. 

Anyhow, a Boost is not a router, it is a bridge from your local network to the SonosNet network. It is advisable to set such a wired product at least one metre away from the router, or other wireless AP.

It’s helpful to set the routers 2.4Ghz band to a fixed ‘non-overlapping’ channel - 1, 6 or 11 with a channel-width of 20Mhz only and to set the SonosNet channel in the Sonos App network settings to a completely different channel. 

There are a few other things you can do too, but just see how that goes when setting up your Sonos HC.

Thanks ,the boost will be well away from the main router ,my house is hardwired and my main router is upstairs and the boost will connect to it via ethernet socket in the living room ,I have a few WiFi only devices in the living room which can be a drain on the wifi network especially when kids are on phones and iPads etc as well,so that's the main reason for wanting to use the boost.

Thanks again for the help 

Given the choice of wiring the Boost or the Beam, I’d wire the Bean and leave the Boost in my spares bin. (where my Boost is)

So does this mean if I connect beam gen 2 to my router via ethernet,it will provide a Sonos wifi network like the boost would so as not to all work over my home WiFi  network ,if so this would be much better and I can certainly do this .Sorry for all the question ,just want keep as much bandwidth on my own WiFi as possible 

Thanks again 

Yes. Just don’t turn off the radio/wifi on your Beam. It will act as a BOOST and all your other Sonos speakers should connect to it via SonosNet (except those Sonos devices that don’t use SonosNet) 

Thats good to know ,the play 1s can use Sonos net so this make it much easier and one less piece of kit taking up a socket and my spare ethernet port 

Yes, the PLAY:1s use SonosNet, except when connected to your Beam as surrounds. When used in that format, they still don’t use your WiFi, but connect directly to your Beam on a different path than SonosNet. 

I have several PLAY:1s and Sonos Ones connected to SonosNet. 

So the beam arrived ,sub not here for another couple of days .Set the beam up and tried adding my play 1s it kept failing ,think it was a issue with my phone ,so tried the wife's phone ,had to add the play ones to the new system first then add them as surrounds ,all good so far but definitely missing more bass for my liking.The beam did set up its own network  that the play 1s connected too and also  Sonos beam media server  on the TV ,now just waiting for the sub .