Usually in your speaker setup, the three speakers are used as the front (with the middle speaker acting as the center channel) and the two speakers are used as the back as surround speakers.

With the Sonos Amps, you will only be able to use four of the five speakers. You would use two Amps - one to power the two front channel speakers and one to power the two rear surround speakers. The center speaker (of the group of three) would remain unused. You can add a Sonos Sub to complete the 4.1 setup.

Another Sonos option is only using two of the in-ceiling speakers as rear surrounds powered by a Sonos Amp and using a Sonos sound bar like an Arc or Beam for the front channels instead of the in-ceiling speakers.

If you want to use all five speakers, you need to use a standard 5.1 AV receiver rather than a Sonos solution.

Thank you for the information. Actually they way the builder did speaker rough ins is that we have 3 speakers in the back and 2 in the front. Does that mean they messed things up and did the wrong setup?

in terms of connecting the five speakers I am thinking of using AV receiver with the subwoofer then have 5.1 system and then use Sonos port to have that music streaming capability 

I believe the builder did it backwards. I have never seen or heard of a three-speaker rear surround setup.

Yes, you can connect a Sonos Port to an AV receiver and stream music from the Port through your 5.1 setup.