I've become more of a self proclaimed master on this i don't need to lay down to do it anymore but.... This is how its done for beginners.
1)Find a conferable and quite area that you can relax in.
2)Close your eyes and let every mussel in your body go limp.
3)Concentrate on looking inward with your mind. This will allow you to achieve a lucid state you can astral project from.
4)Picture a vortex spinning(either direction it doesn't matter) with a point in the middle.
5)Follow the spin of the vortex focusing on the point.
6)Feel your self moving closer to that point and go through.
7)You should be astral projecting.
Note: You shouldn't be asleep during this. It takes a bit to learn how to stay awake but its worth it. Also be careful of were you go. Stay near your body as much as you can help it until you start feeling safer and then you can move around. Some spirits can interfere with you and try to stop you from astral projecting or worse. So keep in mind that not all spirits while your on the astral plain are friendly.
mind mapping is easy. There's a whole bunch of free programms and even apps for chrome that will let you do it to your heart's content. Just google for it!
As for astral travel....
It's easy. It just takes years of preparation to do it for more than a fraction of a second. That includes training to master your mind and to learn how to do lucid dreaming. I doubt you have the gumption to take on the training - even those who believe in astral travelling take YEARS to get to the first plane, and even then, very few of them actually master the travelling part.
SO, your first step: find a master of astral projection, and be ready to not see any results for at least 10 years, maybe even twenty or fifty. You have virtually no chance of learning the techniques without a master to train you and prepare you.