Follow these steps to use the IF function in Excel:

1. In the formula bar, type equal sign ( = ) to start the formula.
2. Type the IF keyword
3. Type in the condition you are testing
4. Type a comma
5. Specify the value if the condition is TRUE
6. Type a comma
7. Specify the value if the condition is FALSE
8. Type a closing parenthesis
9. Press Enter

The IF function in Excel is a powerful tool to enable users to test a condition and return a specific value when the condition is met.