From what you are saying, meditation is a state of mind. How do I know if I have been in that state of mind?
It is similar to having a good nap. You know when you have had a good nap, right? And when you have had food, you know you have had food. It is as obvious as that. You feel so relaxed from within; it is hard to explain. You feel very good and pleasant. There is a sense of pleasantness that comes from within, and one is totally at ease.