Claying is pretty straight froward.
I like to use car shampoo as the lube. I wash the entire car, then re apply the shampoo to one section. Now break a piece of clay(1/4 of the bar) and make a pancake out of it. Now with light pressure(just enough to hold the clay from sliding out from under you hand rub the paint in long back and forth motions.The paint will feel like there is sand under the clay!)relax that is just the surface contamination)
Once the clay glides smooth the paint os clean and the soap can be rinsed off.
Re roll the clay into a ball then flatten into a pancake(this exposes new fresh clay)
Reapply the soap and repeat until the car is done!
Here is an article I did on the subject. How to use detailing clay