Having the primary action on the left before the secondary action is considered better by some designers because it is closer and, therefore, easier to click. This makes sense, but you cannot ignore the fact that users will look at all of their options before choosing which action to take. As they function like pagination buttons, 'Ok' and 'Cancel'... See more

Nothing important should ever be more than two clicks away

The Gutenberg diagram is easier for users to follow when you place the button in the bottom right corner of a dialog box. By placing your button in the terminal area, users will be able to see the primary action last, which improves both visual flow and task flow. Because there is a large visual separation between the two buttons, it is possible fo... See more