To use the RANDARRAY or SEQUENCE function in Excel, first enter them into an empty cell and press Enter. Then, enter the number of rows and columns you would like the array of random numbers or sequences to cover. Finally, choose the desired data type and press Enter again. To ensure accuracy, double check the output for any mistakes.

Steps to using the RANDARRAY or SEQUENCE functions:

1. Enter values: Enter the RANDARRAY or SEQUENCE function into a blank cell.
2. Number of rows/columns: Specify the number of rows and columns.
3. Data type: Choose the desired data type.
4. Press Enter: Press Enter to get the output.
5. Check output: Double check the output for any mistakes.