Nord lead 4 connect to logic pro x

[MyBucchi]

Hi everyone! Finally my little dream come true, I bought a Nord Lead 4. I'm very happy about it. But after several hours of Web searching I actually did not find any information about connecting my Nord Lead to logic pro X. The signal comes to logic via USB, I can hear the sound of software instruments when I play nord like midi device, but I DON'T HEAR ANY SOUND from Lead 4 when I'm choosing "external instrument". Please, help me, tell what I should do to play, record and hear sound from Nord Lead 4 by using USB. Thank you!

[MyBucchi]

MIDI or USB do not transmit audio, only keys pressed and so on. You need to feed your computer with an audio signal from your kbd and record that in an audio track.

[MyBucchi]

Thanks for answering! I'm new about this, I always used a software synths before. Sorry about my stupid questions, but I have one more:
I create the software instrument track, choose the "external instrument", send it to audio, and everything's fine! But when I'm trying to change the program by turning program dial the "external instrument" on the track changes to another software synth EXS24. Help me please to understand what's wrong and how correctly connect all. Thank you!