You start from the expected outcome and think through the preceding steps necessary to reach the outcome
I've found this easier said than done, and the exercise really stretches my mind
It also helps me see potential obstacles WAY ahead of time and helps me review my motives
If done right, by the time I'm ready to take the first action step toward the goal, I more or less have a blueprint to guide the future steps. That beats taking blind leaps into the unknown
Hope this helps someone today.