These circuit diagrams show how switches S1 and S2 flip the voltage to the positive side of capacitor C1 to charge it to 5v and then to the negative side to multiply the voltage to 10v. The charge at C2 is available to another circuit (Vout) or to a resistance load (RL). If more voltage were required, the output of C2 would go to a third capacitor and so on. The switches are actually transistors, but the circuit symbols for the transistors are simplified in this diagram.