Self-made millionaire: 3 things everyone should know about money

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."

The first step to getting rich is focusing on earning, Cardone tells CNBC. "People need to show the ability to produce more revenue — not invest it — first. People get rich because they produce revenue, not because they make little investments over time."

Develop multiple streams of income, he advises. "This does not mean you need to get a second job. Look for other opportunities where you work now that can make second sales (income) or bonuses. Also I joined network marketing groups as a way to broaden the people I knew and give me another flow."

Once you've upped your income, the key to keeping it is to "put your saved money into secured, sacred (untouchable) accounts," he writes on Entrepreneur. "Never use these accounts for anything, not even an emergency. ... To this day, at least twice a year, I am broke because I always invest my surpluses into ventures I cannot access."

Finally, you can focus on multiplying your money, through investing. "Investing is the Holy Grail in becoming a millionaire," Cardone writes. "You should make more money off your investments than your work."

At the end of the day, building wealth can be a simple, three-step process. The key, according to this self-made millionaire, is actually starting with, and focusing on, step one.