Let me give you an estimate of how expansive thinking your brain can comprehend.
Think of Milky Way. Milky way is our galaxy, with Sun, the star (Milky Way has about 400 bn stars ) and planets revolving around it(Milky Way has about 100 bn planets), and planets have their (private cheerleaders!) , like the Moon to the Earth, orbiting them. There is also Asteroid belt. And Universe has many such galaxies.
Now,think of an atom. I could never express succinctly how small an atom is but this might help — An average human body has about 10^27 atoms. Or if an apple were to be made of the size of the earth, the regular apple would be the size of an atom.
Marveled? But about what? What you should be marveling about is that your brain is capable of understanding this information. Not only understand, but visualize!
And this is just your conscious part(10% mind). Your brain has two more segments, sub-conscious(50-60%) and unconscious(30-40%). This was conceptualized by Sigmund Freud. What you just did, processing the size of atom and Universe was the conscious mind in action. Your mind is so much more that just a processor to your surroundings . It is an undiscovered celebrity,it is a tool that can make you or break you.
The conscious mind is awareness personified. It has the ability to gauge the surroundings and operate in it. A developed conscious mind has imagination and focus. The sub conscious mind has short term memory, default programs and reactions to conscious’ imaginations. So if you imagine and focus negative situations, on how pain in ass your job is, you will get a pain in your ass, literally. Sub conscious mind cannot distinguish between real and imagined. All it does is follow commands received as brainwaves from the conscious segment. The unconscious mind, is similar to sub conscious, only you cannot choose what to remember. It holds every thing you have ever experienced, even the things you suppressed( irrational fears should make sense now). It is the main function to all the default programs of your sub conscious mind.
The route to change your reality lies from top to bottom of the Freud triangle. If you focus your conscious mind on what you want, on how you want to be, those instructions will be pipe lined to sub conscious, and with repeated acts, it will be pipe lined further to unconscious, causing what is called a paradigm shift, an alteration in the very basic belief system you have been living with, without any knowledge of it. Some of the techniques to re program your sub conscious mind include—Dreams,Decisions and Goal-Setting, Positive and Negative Thinking,Affirmations, Emotions, Creative Visualizations and Imaginations, ,Uplifting others.
I will try my best to logically explain how these might work to help you manifest your reality, but at one turn, rationality will lose the grip and you have to surrender to the unknown and believe that everything you want is out there.
Your reality is nothing but your vibrations crystallized. And your vibrations are nothing but your thoughts in physical realm.