In order to use the AVERAGEA or COUNTA function in Excel, you need to follow these steps:

1. Open the spreadsheet containing the data you wish to use.
2. Select the range of cells containing the data that you would like to calculate.
3. Open the formula tab and click the AVERAGEA or COUNTA function.
4. Enter the cell range into the parentheses in the AVERAGEA or COUNTA function.
5. Click the Run or Enter button to use the function.

To ensure that you have used the formula correctly, verify the result of the function and compare it to the expected value.