The surrounds bond to the Beam via their own 5ghz wifi. 

So first set up the Beam on your 2.4ghz wifi. 

Then go into the Beam settings and Add Surrounds, and follow the instructions to add the Ones as surround speakers. They will bond to the Beam, you don’t need to worry about what wifi band they are on.

There should be no need to connect the Beam via ethernet.

When you bond the surrounds the Beam creates a dedicated 5Ghz link to them, so just leave wifi enabled on all speakers. 

Are you sure this is a 5GHz link ?
Since the Sonosnet channel selection options are 1, 6, 11, which are for 2.4GH

Yes

Maybe you can expand your answer for explanation.

I believed channels 1 to 14 are for 2.4GHz Wifi

and channels 32 to 135 are for 5 GHz Wifi.

SonosNet uses channels 1, 6, 11 which are 2.4GHz channels ?

WWFR, maybe this will help you understand?

 

But to answer your question shortly, yes SonosNet uses channels 1, 6, 11 on the 2.4GHz frequency.

And the surrounds do not use Sonosnet, but use the dedicated 5Ghz link mentioned above.

All clear, thanks