Normally speaking, you’d connect the output on the Sonos Port to the line in on the Sevens, but I’m not familiar with those speakers. 

Ok, I found pictures at https://www.klipsch.com/products/the-sevens-powered-speakers

Does the ‘phono’ input have a preamp associated with it, or not? 

Ah, I can barely see a switch next to it labeled ‘Phono’ and ‘Line’. Set it to ‘Line’, and connect the RCA output from the Port to the RCA input labeled ‘Phono’ on the Klipsch, and you should be good to go. 

You may want to confirm with Klipsch that ‘Line’ indicates an expected Line level input, which the Sonos provides.

The Klipsch information warns against connecting anything other that turntables but is not clear about the line switch.  I am searching for Sonos  information about the digital connections and which cables to use from the digital output on the port to the digital inputs on the Sevens.  
 

thank you for your help! 

If you look at the connectivity on the Sonos Port, you’ll see it has a coax digital out. Those speakers appear to have an optical input for digital, so in order to use that, you’ll need to get some sort of adapter to change from an electrical signal to an optical signal. I assume those exist, but I’ve never used one. 

There is a 3.5mm AUX input that can be used to connect the Port. You will just need a 3.5mm to RCA adapter.

I believe I found a digital cable for the port to the speakers on Amazon but it is not definite.  Will the quality of sound be affected by the rca vs digital connection? 

What cable cable you find? The Port has an coaxial digital out, your speakers have an optical in. Why not use a cable like this: https://www.audioquest.com/nl/products/tower-mini-rca-interconnect-cable

I will order immediately!  
This is exactly what I was asking for.

Thank you