Hey, I know the feeling, I was also confused because there's no Gate button where all the signal buttons are. So what I found is that when you're looking at your preset screen where you see all the signal chain, single click on that rotating wheel above the Home button (the one he uses to go through the global settings). That will show you one of the elements on the signal chain (there will be a little arrow pointing down to whatever is currently selected). I think the same thing happens if you just long press one of the buttons of the signal chain, for example the amp button. Anyway, don't rotate that wheel, if you rotate it then you change whatever is currently selected (for example you select anther amp, if the amp is currently visible). Instead, push it to the left and you will see that that little arrow moves in that direction and now that element is shown above. So if you were on the amp, then you will move left to the EFX, then COMP, then WAH, then finally GATE. Now you can change the gate pedal and if you press the rotating wheel it will activate or de-activate it. It would have been much easier if they had included the gate button on the right as the rest of the elements, but well. They also forgot to add a button for the Send/Return element. Same thing you can do to select a different Wah pedal.

The relatively less expensive dual processors don't quite have the horsepower to do this.