To turn on the shower you should see two knobs. turning one will make the water hotter, the other colder. you want to adjust these knobs until you get a desired steady flow of warm water.
Done? Congrats! Your 1 step closer to cleanliness

Now, you want to take off your dirty clothes and enter the shower nude. this allows the water to directly clean your dirt covered body, and to also keep your clothes dry.

This step is where most players quit, but your no quitter! after you enter into the shower you will want to grab a bar of soap (example images attatched) and rub it on your body under the shower head. the water and soap mix should clean most of the dirt off your body.

(follow up guide will be made for hair cleaning and for clothe drying in near future)