Instructions
Move the main character to an outdoor location near a water source. The fire will not catch unless there is water nearby.
Press the "B" button on the underside of the Wii Remote to select the character's backpack.
Press the left and right buttons on the directional pad of the Wii Remote to cycle through the items in the backpack.
Press the "Z" button on the front of the Wii Nunchuk when you see the icon that looks like a book of matches. The matches represent the bonfire set, and the "Z" button causes the character to use whichever item appears in the backpack selection menu.
Press "Z" to try again if the fire does not catch immediately. It may take a few attempts before a bonfire appears.
Put the fire out before leaving the area by selecting and using the watering can, which is also found in the character's backpack.