Sequencer and Keyboard

Just connect the Midi Out of the sequencer to the Midi In of the keyboard, and tell the sequencer to use the voices on the keyboard, then as you modify any settings in the sequencer you will hear how it sounds as if you played on the keyboard. (That�s the way I have always done it since I started with Midi in about 1985, when I combined my Atari ST with my Wersi Alpha Organ)
Tip: If you own a Wersi OAS instrument, use Midi 2 for your sequencer, as by default this is set up to directly work with an external sequencer.
Hope this helps

Bill