Just connect the keyboard stereo output to the
mixer stereo input via a jack-to-jack stereo cable.
Via a snake/multicore
Not quite as simple. Most snake boxes only have XLR
sockets. This means that you will need a stereo jack to XLR cable (see
below). At the mixer end you will need an XLR to stereo jack to plug into a
stereo input on the mixer. You can not use the XLR input on the mixer as this
is for balanced signals only.