The problem is, if you want to do something you've never done before, then the steps to that, the milestones, will be unfamiliar.
Analogies are useful for explaining something unfamiliar in familiar terms.
The most important thing you must do to arrive at any destination is start the journey. In order to go somewhere or do something that you have not done before, you will need to step out of your comfort zone. Stress and fear are normal reactions to the unknown. Many people are afraid of the unknown. By trying to do something that you have never done before, you are heading into the unknown.