The IF function can be nested, when you have multiple conditions to meet. The FALSE value is being replaced by another If function to make a further test. For example, look at the formula below.
1a. If cell A1 equals 1, the function returns Bad.
1b. If cell A1 equals 2, the function returns Good.
1c. If cell A1 equals 3, the function returns Excellent.
1d. If cell A1 equals another value, the function returns No Valid Score.
Here's another example.
2a. If cell A1 is less or equal to 10, the function returns 350.
2b. If cell A1 is greater than 10 and less or equal to 20, the function returns 700.
2c. If cell A1 is greater than 20 and less or equal to 30, the function returns 1400.
2d. If cell A1 is greater than 30, the function returns 2000.
Note: to slightly change the boundaries, you might want to use "<" instead of "<=" in your own formula.