Go inside the mill and pull on the rope that releases the gear lock. Now the arms of the windmill will turn. Go counterclockwise and watch the roof dome.
The mill gears on Astro Knights Island are in the second-floor loft of the mill, and they are locked to prevent the windmill arms from turning. Grab the short hanging rope to unlock the gears. Go outside and turn the windmill arms counter-clockwise by climbing on them, and you will see the roof dome open.
Inside the windmill, climb into the loft and hang on the rope. This will release the gear lock and allow the windmill arms to turn. Jump up on them to turn them counter-clockwise, which will open the roof dome.
1:turn the windmill blades clockwise
Once you hang on the rope, you unlock the gears and the windmill's arms will freely roate. Go outside and turn them counterclockwise to open the roof dome.
Go inside the mill, up into the hayloft, and pull the rope that is attached to the gear lock. Now the windmill arms will turn freely in either direction. Turn them counter-clockwise to open the dome. (see related question)
The gears in the mill on Astro Knights Island are locked by a small catch on the inside. Pulling on the attached rope unlocks the gears and then you can freely turn the windmill arms by jumping on them. (Turning them counterclockwise opens the roof dome where the hovercraft is stored. Adding manure will send it over to the mud swamp where you can use it.)
You can't get the hovercraft from inside. Unlock the gear lock and go outside. Climb on the windmill arms and turn them counter-clockwise. This opens the roof dome.
Go inside the mill, on the second floor, and hang from the rope that unlocks the mill gears. Then go outside and climb on the windmill arms to turn them counter-clockwise. This will open the roof dome. (see related question)
Climb into the loft and pull on the rope to release the gear lock. Then climb on the windmill arms so that they turn counterclockwise. This will open the roof dome. The hoverboard is powered by manure.
Climb into the loft and pull on the rope to release the gear lock. Then climb on the windmill arms so that they turn counterclockwise. This will open the roof dome. The hoverboard is powered by manure.
Once you have opened the attic dome, you can add manure to make the hovercraft work. To open the attic, release the gear lock and turn the windmill arms counter-clockwise.
To get to the hovercraft in the attic of the mill, pull the rope to unlock the gears. Then go outside and turn the windmill arms by jumping on them. When they turn counterclockwise, the roof dome will open. Add manure to the hovercraft and it will go to the swamp.