If you carry a credit card balance, the minimum payment is a "need" and it counts toward the 50 percent. Anything extra is an additional debt repayment, which goes toward this 20 percent category. If you carry a mortgage or a car loan, the minimum payment is a "need" and any extra payments count toward "savings and debt repayment."
The most important of these is automatic savings. Open a savings account, and set up your checking account so that you automatically transfer a set amount each month into your savings account. You don't have to transfer much money _ start with whatever your budget can afford. But making this automatic (and then resisting the urge to spend the money impulsively) will get you on the road to long_term savings.