If you can devote some time please read this page on Wikipedia to get some answers.

You may get confused for your first question "How does one actually meditate?" because there are as many methods as number of faiths in this world multiplied by no of authorities in those faiths. Chose the one which is closest to your liking.

For me, I am from India and we chose a Guru first and then follow the method/s suggested by the Guru. I personally tried the 4 methods and settled on one which I liked.

Relaxing is Meditation if your mind is at rest (meaning there is no thought) which is next to impossible for common man. Relaxing is Meditation if you are watching the thought without any attachment (if you get what I mean by attachment). If you find that you are attached to thought than Relaxing is not Meditation for you.

Sleeping is not Meditation for common man.