There are a few possibilities, totokey
Some performances have 1 patch per midi channel, so if you're playing your keyboard, then you'll only hear the patch on the midi channel your keyboard is using.
Other performances have layers of sounds on the same midi channel.
In perofrmance mode, you can select patches 1 to 128 for each of the 16 channels by using the value & channel knobs. I don't think you can select performances from the unit itself - you can change performances either by program change messages if you set one of the midi channels as the control channel, or with a sysex message if you set the control channel off.
To get "nid" on the display takes a little practice - read the manual, but from memory, you have to set one or more knobs, then press in a couple of the knobs, then turn the power on, then keep one of the knobs in for at least 3 seconds.
GM Arts