Obviously we exist as a part of the "source" or in my religion, God. God made us and the universe therefore we are a part of "him"...in a manner of speaking. Energy is energy, nothing supernatural or esoteric about it.
From a strictly scientific perspective, what we perceive as reality is a mix of real-world events/things and an illusion our minds create to make sense of it all. If we look even deeper at quantum mechanics, we exist in the solid state we're in solely because others see us, and they exist because we see them. Furthermore, we are here because the universe is here and it's here because we're here. Basically, the "pressure" of the universe on itself makes it a reality and nothing you can do can fundamentally alter that.
As for manipulating reality. We can to a degree and as Oceanne said, we do it by making choices, actions etc.
There has been a school of thought for thousands of years that has taken many forms. Simplistically, it suggests if we can think, wish, want something hard enough it will happen. I see zero evidence of that and if it were true all of those "sages" would be ruling the world or would have had much better success at teaching it to millions of people. Instead, a good many of those people are in jail for embezzling funds and otherwise living high off the backs of the naive and simple minded.
If the "many worlds" theory (in physics) is a correct one then every action, thought, breath you take creates a new universe with its own reality. However, you can't exactly "will" something into being within the universe you live in....each action creates a new universe, separate from this one.
The "proof" and stories people tell of wishing for a good job and then *poof* they got one is nothing but a misunderstanding and a logical fallacy. If I live life with an eye to advancement, in a good mood etc, then chances are my life will be better. Not because of any mystical powers but because of simple human behavior. Basically, if you're in a good mood, your stress level goes down, you feel better, your judgement clears, and the odds of something good happening are increased bc you're better able to recognize it and people are more prone to helping those they like (i.e are in good moods).
Likewise, if I "wish" enough for money, health, or whatever then my brain is simply focusing more on those things and so when an opportunity arises I am more likely to see it and pay attention. It doesn't mean I made the opportunity happen.
To put it another way, it is little different than this scenario: If I think women drivers are horrible then my mind hyper focuses on events relating to poor drivers who happen to be women, all-the-while ignoring the countless examples of good women drivers. A self fulfilling prophecy mixed in a clouded perspective in other words.
