I need help with the very basics of finding z-scores from the point of assuming I know nothing.

a distribution has a standard deviation of mu=4. Find a z-score for each of the following locations in the distribution.
above the mean by 4 ponts, above by 12 points, below by 2 below by 8 points

If I could be shown the formula and how to place the numbers, I can do it myself. (show me one of them). I believe I know the formula as z=(x-mu)/s

Thanks for the help. I need this soon.