If the thought of investing in bonds overwhelms you, you aren't alone.

Between the different types of securities and the varying yields available in the $43.1 trillion dollar bond market, investors may have a hard time sorting it all out.

Yet if you want a balanced portfolio, experts say it's important to include fixed-income assets. That's because stocks tend to be riskier, while bonds are considered a safer investment. In fact, the age-old rule of thumb is the "60-40" rule — which means 60% of your portfolio should be in stocks and 40% in fixed-income.

So, what do you need to know when it comes to bonds?

CNBC on-air editor Rick Santelli has the answers to five key questions.