you have to apply opt before you graduate. you get 60 days of grace period , but that is if you are to leave the country or change your status to something else, like going to masters programs and get an i20  for that or change of status to h1  you can dealy your opt for that grace period by applying late but what if your ead don't come on time, then you're screwed/. yes i765 is the form for work permit, and you have to select the right code. you have to bring that form back to your ipo to get it checked and she usually put note on yuor i20 stating applied for opt on the back of it. once you get an opt do not forget to report your job to your ipo advisor, or else sevis won't get updated and you'll be in trouble there is a 90 days rule for that. since you are a business student, you won't get a stem extension, so forget about everify and extension related to STEM degrees. start looking for jobs and apply for opt, i think it takes about 3 months for work permit to get approved now a days , double check at uscis.gov . just my suggestions so please do your rearch and you're already on the right track btw. 

good cluk