“The present moment is the only time over which we have dominion.”

Simplified Meaning:

Right now is the only moment we can really control. We can't change the past because it's already done. We also can't predict the future with certainty because we don't know what will happen. Imagine you're holding a candle that's lit; the flame is your present moment. You can only control the tiny part where the flame is burning now, not the part that has already burned down (the past) or the part that hasn't been lit yet (the future). If you spend all your time worrying about what has already happened or what might happen, you miss out on what you can do right now. For example, if you didn't study for a test last week (the past), you can't change that. But if you have a test tomorrow (the future), you can choose to study now. Focusing on the present moment allows you to make the best choices with what you have control over right now. By doing this, you can create a better future for yourself. In short, make the best use of your time right now, because that's the only time you can actually do something about.