Vortex Sound Research

Some of you give me a lot of warmin advice and lovely suggestions but, i Guess it's me, can't understand the MIDI right connection between Arturia Keystep and Behringer ModelD. In the box of model D there Is a simplex set up.

KeystepMIDI out==> ModelDMIDI in==>Earphones

But the two fuckerz wont works.

So i'm nearly to give them some fresh water!

They're brand new. So Then, it's me. Maybe Midi for dummies should be a subreddit for my twicely request. Sorry for my itaenglish too.