Audio setup with a split cable

I am trying to set up the Djay 2 for iPad audio in order to accordingly split the sound into my headphones and speakers for respectively cue up the next track on my headphone and hear what’s currently playing on the speakers at the same time. I set the split output on and plugged a split cable, but one speaker (the left one) is working with the current track while the other (the right one) speaker is working with the next track (the pre-cueing). Similarly, I am hearing both the current and the next track at the same time with my headphones. I could not access the “audio device set up” for trying changing the audio channels. That screen (which I only could see in the manual) does not appear when pressing the settings button.