Understanding the 'I am', your sense of 'being' or just 'presence' is extremely important as on it rests the entire outcome of the teaching. Firstly, are you at all aware of your 'being' or of the fact that 'you are'? You have 'to be' before anything else can be, your sense of 'presence' or the feeling 'I am' is really fundamental to anything that has to follow. Secondly, this sense of 'being' or the feeling 'I am', was it not the very first event or happening before any of your living experiences could begin? Apply your mind go back in time to the moment when it dawned on you that 'you are' or 'I am'. This 'I am' is still there with you, ever present, ever available, it was and still is the first thought, refuse all other thoughts and come back there and stay there. So try to understand and grasp this 'beingness' or 'I amness' that is inherent in you. The more precisely and clearly you do it the more rapid will be your progress.