HELP ! Midi Connection of my Tyros 4 and New Synth

[Jeff Hollande]

Hi Guys :

I need your help.

I want to connect both instruments ( Tyros4 and Synth ) and use my Ty4 keybed only to play both instruments ( arranger or synth independently ), if possible. 
I have never done this before though. 

What is the right connection ( in + out ) and best midi setting(s) to get optimal results ?

Yesterday I ordered a pair of DIN cables ( 5 pins ) that will arrive tomorrow, I guess.

I am looking forward to reading your reaction.
Thank you so much for your help and support.

Kind regards, JH