I want to learn how to astral project?

In the past weeks i've been feeling an urge withink myself to get more in contact with my spiritual self. I have been having the 11:11 experience and I want to start to astral project or to do something like it but i dont know how. Can you plz tell me how? and i've also heard that I have to learn how to protect/shield myself first? does anyone know more about this? THANX!