Grant Cardone knows a thing or two about managing money.
The entrepreneur has built five companies and a multi-million fortune — and he earned his first million before age 30.
"There are three things people have to know about money," Cardone tells CNBC. "Number one is: How do I get money, more money? Number two: How do I keep that money? And number three: How do I multiply that money?"
Building wealth requires three, simple steps. However, "most people want to know number three before they know number one and number two," he says. "Everybody wants to know how to multiply, but they don't even know how to earn yet."