Typically medical students take 2 - 4 weeks for preparation. Depending on whether you are an American Medical Graduate (AMG) or an International Medical graduate (IMG) the timing of preparation will vary as you will have to factor in, training yourself to interact with a patient the American way! You also need to consider travel time to and fro from your country. Some students need 2-3 months to improve their Spoken English proficiency and/or typing speed as the patient note has to be typed and not hand written.