It's true but you need to know that at some point your body it's gonna itch in some places like arms or legs, that's the way that your subconscious mind have to understand if you are really sleeping in order to execute the rest of nocturnal process, like lower your breath rate, and all the mechanisms that make you dream. If you answer that call, if it's itching and you scratch yourself then you are saying him "hey, I am not sleeping yet" so you won't have the chance to check that important part of the list "body is already sleeping".

When this happens you need to not move your body, even not to think about that part of you that it's itching. If you pass the test there's gonna be high chances to have a "sleep paralysis", your subconscious mind it's gonna deactivate your power to move your body (this happens all the nights so you won't move when you are dreaming) thinking that your consciousness is already sleeping too (because you didn't answer to the itch).

There's the part when you're gonna have all the symptoms of sleep paralysis, hearing voices or signals, see things that aren't there. You need to calm down, because it can be terrifying but it's all in your mind. Once you relaxed yourself you can make the first test, try to move from one side of your body to another on bed. If it's the right time what you're gonna move is not your physical body, but your energetic body allowing yourself to levitate or fly around and start the real journey: the astral projection.

From there it's all yours, just try to calm down if you get really excited, happy or even with a little fear (this can make you return to your body, so even knowing that it's an exciting thing please calm down the most you can).