The main purpose of I Am is to know the thing every seeker is wishing to have: the Reality. At first it is honestly not easy to grasp what Ramana meant with I Am practice. He said remain in I Am and if one is ardent in this, he will understand who or what he is. But seekers are at lost what this I Am is all about. What kind of idea is it? How to implement it? How to begin it?
Reality can be known through I Am. There is one short explanation of this I Am which beginners could start from. I Am is simply a feeling. How is that? Being aware that you are here reading this piece is an I Am feeling. I Am is the the feeling that you exist. You can begin from this inherent sense that you do not don't exist. Whenever you are aware there is a feeling of existence amidst everything happening around. That is the I Am feeling.
You are never not aware. This is I Am feeling. Remaining in it will bring the understanding who you are. You are the unconditional bliss. Nothing more. But you need to know and verify it yourself. It can be done through the practice of I am.