How do you properly extinguish a campfire to ensure it is completely put out and safe?

To properly extinguish a campfire, follow these steps:

1. Allow the firewood to burn completely to ash.
2. Pour water over the fire, stirring the embers with a shovel.
3. Continue adding water until the hissing sound stops.
4. Use a shovel to mix the ashes and embers with soil.
5. Feel the ashes to ensure they are cool to the touch before leaving the site.