I assume you also want to listen through passive speakers connected to the marantz?

Does the Marantz have an output such as a Tape Out? I'd be a bit surprised. If so you could connect this to the RCA input on the Port

If not then you could connect your CD player and turntable to 2 of the 3 lines in available to you (one on the Port and one on each of the Fives). You may need a phono pre-amp for the turntable. 

The Port could connect via RCA or coaxial to a suitable input on the Marantz. 

Thanks John. No passive speakers. Only using Play 5s. 
yesterday I connected the turntable to the phono input on the amp, the CD player to the CD input on the amp. I then  connected the RCAs from the audio out on the amp to the audio in on the port. There was a constant buzzing sound from the play 5s and then when I put the turntable on, the music was completely distorted. The port’s manual says to connect the RCA from the ‘Out’ to the Amp. But where on the amp? Should I use any input on the amp? And if I did this, how would the music come out from the Amp to the Play 5s?

thank you. 

Looking at the Marantz amp pm7000n you use the audio out ports which are marked Recorder, can you confirm you used these?

The turntable input on the amp has a ground wire post, this will help eliminate hum from the turntable so connect the turntables ground wire to it.

You are using an amplifier as an RCA switch/preamp. Why not just use a preamp and an RCA switch? Would that not have been much cheaper?

Hi, thanks. Yes, I connected from the audio out ports marked recorder on the Amp to line in on the Port. I grounded the turntable but didn’t ground the RCA cable on the amp. I will try that. I was so disappointed yesterday, I packed up the Amp to return it. 
Until yesterday, I was had connected the turntable to the port and the CD player to my Garden sonos amp. The plan is at a later that to get the KEF LS50 metas wired to the Amp, but until then, I would want to use the Play 5s. 

Deleted

Thank you. Didn’t think of a Preamp. I bought the amp because in the next 2-3 months, I want to get passive KEF LS50 Meta speakers. Currently as my response to Belly M, I use the play 5s with the Sonos Sub mini. The sound is really very good. The turntable already has a preamp, its Project Evo turntable. I am unsure if I would achieve a major difference with the Marantz and the passive speakers!

Ah, you already have a phono preamp!!

So do not connect the TT to the phono input on the amp, use another spare input, the AUX would be a good one.

EDIT

OR  ensure the phono preamp is turned OFF and then use the phono in on the amp.

Yes, thanks , I turned the switch to phono on turntable, that would disable the built in preamp.  Will take the amp back out from the box and try later today and will update.  Thank you. 

Thank you!

Perfect, this worked. Sounds OK with the Play 5s. I am sure it will be better with the passive KEFs.

Regards

Mayur.