That part isnt too clear, you're right.

What happens, is that when your well gets 200 points of energy, a cannon appears.
Use this cannon to knock away the castle and capture the well.

with a budger attached,
keys 1,2 aim the cannon up and down.
keys 3,4 aim it right and left, or you can push it physically
key 5 fires it, or you can shoot a fireball at it.

:king: