The Universe is an infinite number of vibrational frequencies and consciousness, pure infinite energy, permits the traveling from one vibrational frequency to another. When you think about the infinite possibilities of the Universe, such as an alternate life in a parallel universe, you are at that moment witnessing alternate universes in a way, since you are at that moment witnessing specific vibrational frequencies that match the thought you are thinking.
When you think about what you want as if it is in your current reality, you are at that moment experiencing an alternate universe where your desires have been fulfilled and this will continue to occur until you switch your focus back to a universe where you do not have what you want. This occurs, because as you are giving your attention to your desires, you are at that moment giving your attention to vibrational frequencies within the infinite set of vibrational frequencies at your disposal that match your desires and when you switch your focus away from your desires, you are at that moment experiencing an alternate set of vibrational frequencies that do not match your desires.
For this reason, as long as you are focused on the fulfillment of your desires, the vibrational frequency that matches your desires, you will have experiences that match your desires. When you are thinking in a way that makes you feel as if your desires have already been fulfilled, you are at that moment giving your attention to the vibrational frequency that matches your desires and you are at that moment experiencing the fulfillment of your desires.