Have a problem with my MX49, can't select the voices

Hi guys. Basically I can’t select the sounds for any channel besides 1 (and 2 maybe I think).
I select the channel in Cubase AI (which comes bundled with the synth) but when I select a voice on the MX, nothing changes. Sometimes I get a set of default sounds which I think is because I’ve been playing around with the performance button but I just cannot choose the sounds I want. Can anyone shed any light on the subject? I would greatly appreciate your help.

Have you tried this? https://yamahasynth.com/resources/mx49-mx61-mx88-cubase-win-computer