what about the social security number ? do i have to start any procedures once i entered USA?Congratulations !! Remember to pay the green card fee (online, look up USCIS immigrant fee if the info is not given with your visas), preferably before you go. That's the only formal thing that you need to do.
also i made my medical test on 10th of march so do i have to travel to USA before 10th of September (the 6 months validity) or the only time limit is the visa expiration date?