The Ultrahand ability allows you to pick up an object, rotate it, and then attach it to other objects. Controlling Ultrahand will take some practice at first. When you move something around, you’ll see where two items will attach (the attach point kind of looks like green glue). Pay attention to these attach points and you’ll be building elaborate creations in no time.
If something didn’t attach correctly, just highlight that specific part and gently wiggle your Right Stick to detach it.
Bonus tip: some Zonai devices activate when you smack them with a weapon – just be careful to hit the device and not the rest of your creation. For example, swinging an axe around on a wooden boat is not the best idea…