track input for AKAI MPK mini play

I connected my AKAI MPK mini play with my Mac. I configured the AKAI so that the drums goes out in a different channel to the keyboard. Now I want to configure in Garageband one instument (piano) for the keyboard channel and one instrument (drums) for the drum channel. I found videos in which it is explained that you can choose the input of a track, but I don't find that option in my Garageband track options.

Does someone know how to split the two input channels of an AKAI MPK mini play in Garageband?