The Sonos System requirements are shown here:
https://support.sonos.com/en-us/article/sonos-system-requirements
I would note the section on unsupported network configurations as any network using wireless range extenders are not supported but may work in some instances.
I would set the extender to broadcast the same SSID and use the same credentials, channels and channel-width, as your main router - ideally set the channel-width to 20Mhz only on the 2.4Ghz band and use a ‘fixed’ non-overlapping channel, either 1, 6 or 11.
To setup the Play:5’s (from factory reset state) you will need the S1 Sonos controller App installed on a compatible mobile controller device. Simply open the App and follow the on-screen instructions to setup the Sonos system.Household. That’s assuming you do not have an existing Household that you wish to use?
The mobile controller device requirements are shown here…
https://support.sonos.com/en-us/article/sonos-app-requirements
The S1 App can be downloaded from here:
https://support.sonos.com/en-us/downloads
When the device setup is complete you can then add your chosen music services to the App for playback on your speakers, which can each be used standalone, grouped or stereo paired.
Some further links you may find helpful:
https://support.sonos.com/en-us/home
https://support.sonos.com/en-us/article/add-a-music-service-to-sonos
https://youtu.be/1FUphIbkom0
https://youtu.be/hqKMxhYPjEk
Hope that assists.