Is it true that if I get paid on a salary basis I am not entitled to overtime?

No! If you are paid a salary you may have right to overtime. The law begins with the presumption that everyone is entitled to overtime and then begins carving out exemptions to that and if you qualify for one of those exemptions the employers allowed of pay you a salary regardless of how many hours you work. But if you’re outside when those exemptions your employer has to pay you overtime even if they’re paying you salary.