Witness Voting how do you use it ?

Actually, what is the purpose of Witness Voting whether it really helps to get our income or even helps the income of people chosen.

And is it true if we choose the right person that person will help? And if I'm not mistaken, what's the real advantage of the system that applies to Steemit in this matter. Please answer as clearly and simple as possible.

Do you want to help me to get answer and get money from Steemit ?

And sorry if I'm too stupid to understand clearly about this.