As noted previously, the Informational Note of Sec. 220.40 is really two notes contained in one.
First, it tells you to see Informative Annex D, Examples D1(a) through D10. These walk through various calculation scenarios, illustrating how to perform the calculations in a Code-compliant manner. Time spent here to learn calculation methods is time well-spent.
If you don’t have time at the moment for such study but need to perform a particular set of calculations,