I am having trouble with my excel class. Setting up formulas. I am not sure how to set up this formula with this task. :

in cell i11, enter a formula using the if function and structured references that tests whether the value in the tier field is equal to "platinum". if it is, multiply the value in the total sales field by 0.05. otherwise, enter 0 (zero) in the cell.

Can you help me set up this formula?