MOowhaahahaha ha!!!!
Are we scared yet?
Here we go. The first thing you have to master is getting the astral body to get out of your body and go where it is supposed to.
I know, there are tons of different methods for doing this and all of them work so do not think of this as the only one. If you have your own way of getting out and about please do not fee any obligation to change it.
The first thing you have to do is relax. I am not a great fan of the progressive relaxation technique that is commonly taught for the simple reason that I have a condition called lazy leg, which is anything but lazy and if it try to use the progressive method rather than my legs relaxing it feels like I have weird electrical things going on inside of them, which is exactly what is happening.
The method I use is much simpler. You sit in a straight-backed chair, with your hands on the chair arms or in your lap, feet flat on the floor. This makes falling asleep less likely, a problem I always encounter if I try to project laying down.
Once you do that, the rest is the work of the imagination.
Sit comfortably and imagine that you are standing up. Feel yourself standing up in front of your body looking in the same direction your physical body is facing. That is all you have to do for the moment.
Once you have done that, get used to your new body. This is not the usual mental projection that is normally done with the aid of a radionic box and helmet, where you put your mind into another part of the world. This is a full body project and you have to operate as a full body, not just parts of it.
After you have gotten used to that, take a walk around the room. It gets really tempting to go through the walls and head out into the rest of the house but resist that. You are still practicing. Feel the movement of your legs and arms as you walk, the floor under you. You are still half in the physical space even though you do not feel like it. You want to keep that connection. No flying off to Jupiter this way.