Astral projection (or astral travel) is a term used in esotericism to describe a willful out-of-body experience (OBE), a supposed form of telepathy, that assumes the existence of a soul or consciousness called an "astral body" that is separate from the physical body and capable of travelling outside of it throughout the universe where it interacts with other astral bodies and is capable of implanting ideas into other people's minds. Source Wikipedia
I'll also leave the link to the site for you to read.
As on how to get there, I only achieved it once, first I would meditate, lay down somewhere soft, like your bed, relax your muscles, your mind, and your body. Now in your mind think about getting up, but not physically, think about your surroundings, see if you can see your sleeping body.
That's how I did it, but other people might have better ways.
Essentially, when things begin to exist, they begin at an abstract level, of being the All, a homogeneous static soup of everythingness, devoid of any traits, which in order to experience itself from a different angle turns into diverse, dynamic, individuated, things on this plane we are in.
As it acquires these qualities, it gains solidity in different ways, acquiring causality, on one level, form on another, et cetera.
The final level is the physical plane, where it has all spiritual qualities, though no material qualities, aside from more subtle effects on the material world, the world we live in.
The next-to-final level, devoid of substance but containing everything else, the place where you'll find Asgard, the Underworld, reflections of worlds here, the past, the future, undeveloped, fantastical worlds, demonic empires, essentially anything that can be classified as "the Spirit Worlds" and so much more; that is the astral plane.
Anyway, if you consider your body as being something of a space suit, that lets your consciousness interact with the physical plane, then you would get to the astral plane by projecting to it. Removing the physical space suit, and using the astral body, which is the astral space suit, that's right underneath the physical one, what we label our spirits.
Essentially, you project your consciousness, from the body you are in, into an astral body of light structured outwards from your physical body, to interact wiht the astral plane on an astral level.
It's much less complicated than it sounds, and this entire sub-forum is dedicated to this.
Well I was able to do Astral Projection for about 7 years, To get on the plane I just clear my mind and just lay there until I lift away and can go to places, I don't stay in for very long however.
I am also able to communicate through AP as well.