So prepare to do that 16 times (using the software + mouse & keyboard should be a lot easier).
You can only set MIDI output on a per-sound ('pad') level. There you'll find the option I marked last. Then press the page-right button (2nd marker from top) to hop over to the 3rd page of the output section. So press 'channel' (upper left button) and then select the 'Output' section as shown in screen.
my phone doesn't seem to have auto correction for stutters)