The How can be copied.

The How is a guide. The How includes the What and the Where. What to do, what not to do, what to keep, where to add, where to remove. The How is collaboration. Somebody else can follow your How, and you can follow theirs. 

The Why can’t be copied.

The Why is unique to you. Your Why will be different than somebody else’s Why. Using somebody else’s Why in place of your Why won’t last long.

Why moves us forward when How can’t.