Tbh it's not a matter of "learning" the controls, they're just garbage, even after playing it for hours and hours looking between the two screens is just awful.
You can still learn them, though. When you do, you realize you don't have to look between the screens, the Gamepad alone is enough 90% of the time. And yeah, looking down at the Gamepad 90% of the time isn't what I'd call a good thing, but neither am I trying to say the controls are good, because they aren't. They're a gimmick that's hard to get used to and bring nothing interesting to the table, thus rendering it pointless. I'm just saying the game has other problems that were overlooked because people didn't bother learning the controls in the first place.