It is a simple procedure, Take allthe necessary documents to the school international officer, he will file for u for the change of status from H1 to F1, there will be some fee abt 120 dollars i think so.So check with u re internatinal department in school they will take care of that.
Think one more time before changing of status, that is a non immigrant visa, and in the change of status there wont be multiple entry , if u need to go to india in near feature then u need to get stamped on your passport for F1, so think all the things as per the situatuation and go for that.