Showers are included in your Camp Contact dues. To use them, just indicate it in the Showers question on your registration form so we can plan water supplies. You can see who else is signed up on the camper showers list.
Your current shower choice also appears in the My Amenities section of your dashboard, with a link that jumps straight back to the form question if you need to change it.
Camp at a Burn:
Camp Contactat Burning Man