When washing your car it's important that things are undertaken in the correct manner and right order, to prevent any potential damage from being inflicted, and to also ensure that all areas are thoroughly cleaned and that nothing is overlooked or missed. If you regularly wash your car yourself, you may already have your own routine that works for you and the needs of your vehicle and this is fine so long as the final outcome is satisfactory, and more importantly, that nothing is being jeopardized during the routine.
Again car wash products for home use have advanced to a point that there is zero water waste to be dealt with. No waste means minimal impact on the environment. Some of these products that produce a few gallons of waste water are so eco friendly that they can even be used to water plants!
So yes, you will need to clean the microfiber towels. The towels can easily be washed by letting them soak in a 1-gallon bucket of hot water with a little dish detergent. If you have a bunch of towels, save them all up and do one full load versus cleaning individually. There is also the misconception people have that the towels are disposed of after one use. Not true. The average microfiber towel can be wash and re-used up to 50 times. Considering that the average person cleans their cars once ever two weeks, the towels will last you for about two years before disposal.
Once the wheels initial scrub is complete, the main car wash can begin. You start by rinsing the car, beginning at the top of the car and working your way down. Be sure to pay special attention to spots where dirt or debris may accumulate. A good tip here is to pull all of the windshield wipers away from the glass into the propped position prior to rinsing or soaping the car.