Please get an expert to help you with your new colt. I have a good amount of experience with horses, but since this was my first young one I have several times asked advice from the trainers I know, and they have helped me along in the learning process, both for my colt and me:)
Will your colt be living with other horses? This will be very beneficial to him, both for his mental and physical health. Also, the more dominant horses will teach how to be submissive and respectful, making your job much easier when you begin to establish leadership over him.