You may want to review multiplication of many numbers first.
Powers look like this: 53. That means you multiply 3 copies of 5 together, like so: 5 * 5 * 5. The big number on the bottom (5 in this case) is called the base, and the small number up top (3 in this case) is called the exponent.
The base could be a negative number or a fraction. The exponent, though, will (for the moment) always be a whole number.
If the base is a negative number or a fraction, we usually write it in parentheses, like so: (−3)2. This means (−3) * (−3), which is 9. Without the parentheses, −32 means −(3 * 3), which is −9. Remember: minus signs not in parentheses are applied to your final answer.