Self-serve car washes are not the conveyor belt type with big brushes. Rather, they are a hand car wash station where you can enter and park the car. This video details how drivers can use one of these stations to clean their vehicles.
The stations are typically unmanned and require one to wash their car using a spray manually. The advantage they offer is that they are cheaper and less damaging than automated car washes, which can damage paint and parts such as the antenna.
When parking in a self-serve car wash, do so in such a way that leaves room to walk comfortably around the car. Also, park close enough to the sprayer to ensure good reach on both sides of the vehicle. Knowing the kind of payment the machine takes beforehand is also wise. After paying, move on to the sprayer, where various wash settings are displayed. Though there are more settings, drivers will most likely only need the wash, soap, and rinse settings. Set the sprayer to wash and get most of the dirt off the car. Follow it up with soap and use the provided sponge to scrub the car. Finally, rinse the car entirely.