i have got a rank 0f 677 in preparatory course st category .will i get seat in a iit and after completion of preparatory course would i go to 1^st year or 2^nd year

If you get qualified in JEE advanced it is obvious that it is your entry to the IIT.After the completion of your preparatory course you are allotted to the respective branches basing on the examination results that are held in your prep course so that you’ll start ur undergraduation program i.e., 1^styr. Dont worry. All the best.