If you have a speaker from your existing system you can ‘seed’ the new system by just following the instructions for changing router or wifi.  Because that is all you are doing, really.  This way any playlists, settings etc from your existing system will be preserved.

https://support.sonos.com/s/article/1061?language=en_US

(If you want to make things even simpler you could try changing the SSID and Password in second home to match those in your first home - speakers may then just connect.

If the speakers for the second home are new then just follow the standard new system setup instructions.

https://www.sonos.com/guides/setup

Connect your mobile to your second Home WiFi network and with either a ‘new’ or ‘factory reset’ Sonos device, simply create a new Sonos Household using your mobile Sonos App - continue with the setup for all your devices on that different LAN/Network. 
 

Close App on leaving that seconds Home (it’s not necessary, but keeps things tidy) and on reconnecting to the network WiFi at your first Home, you will just see your local Sonos system when you reopen the App. You can just switch between the two by simply connecting the mobile controller device to each local WiFi network.

rodrighx,

The answer I have given is slightly different to John’s above, as I was assuming you wished to have two entirely separate Sonos systems at each of the different locations, perhaps with some same-named rooms etc; but you can just extend the existing Sonos Household too and have them operate under the same HouseholdID as John is suggesting. In my own holiday location I chose to operate the Households separately, but with the same controller, which switches systems, depending on which WiFi network it is connected to. So it may depend on the type of setup you prefer to put in place.

Thanks, Ken! My fear was that doing the new installation at the second house would wipe out the first house’s settings and when I returned would have to set up all my components again. I’ll set up the second house with the speakers and hopefully when I return it will be no impact when I’m under the other wifi!

It will be fine - you can even have two (or more) separate Sonos Households on the same WiFi connection, at just one home location. (Perhaps that’s for discussion another time ha ha)