Video by Korg via YouTube
Source
On the main panel there are some part control buttons!
What you’re gonna want to focus on are the top row where you can customize what your triggering on the main keyboard!
If you want to adjust what is on each layer, just simply hold "Shift" and hit any given layer! Now you have access to the over 700 sounds, OR if you select catagory, you can jump through different catagories within those 700+ sounds
Adjust your volume balance simply hold one of the buttons and rotate the dial to adjust that on each layer!
If you want to hear what is happening in the lower you MUST have SPLIT turned on!
Click here for more information on the EK-50U: https://korgusshop.com/products/ek50u