We drift through the astral plane in dream, trance and when we project. The astral plane possesses it's own matter that acts like thought matter, reacting to and aligning with the thoughts. When we project we leave physical reality and enter the astral plane.
There are many methods for doing so, such as taking control of a dream while sleeping or hypnotic trance. I will provide my own method.
1. Inhale slowly, hold the breath a while, exhale slowly, hold out a while, repeat; take one last deep breath and just relax, ignoring any thoughts.
2. Let the body breathe on its own, ignore the body and move as little as possible.
3. Stay this way for a while.
4. Imagine you're moving about in a body (any form you wish) and form some scenery to move about in. You are now on the astral plane.