New Keyboard not listed in Instrument Definition

I had a PSR 740 keyboard connected to my PC for Sonar 8.5 using a midi lead but I have just purchased a Yamaha PSR S910 and the guy on the phone said that I would just need a normal USB cable to connect.  I have downloaded the new driver and now in Options midi it shows  additional digital keyboards 1 & 2 in the list, that was not there before as well as my old 740.  Clicked on digital 1 in and out and now want to assign instruments so have gone to Options/Instruments and new keyboard not shown on right even though I´m clicking on digital 1.

Been such a long time since I assigned the instruments for the 740 I can´t remember what to do.  Should I go back to my old midi lead as maybe that is the problem.

Can you help this lady in distress please!!!  Please tell me in easy language that I will understand

Many thanks