Find the email of the international student admissions from the university website of the university you are interested in. Ask them how can you be admitted. Fill out their application. And keep emailing them asking about the status of your application. They will ask you questions or additional documents. Your job is to provide them with documents they ask for. Regarding your 3 yrs BBS. They will verify if the degree is from an accredited univeristy and the courses that were taken are equavalent to their offerings..
In simple terms you might have to take few classes to complete your BBA or whatever bachelors degree you want and then only move on to Masters level. It works pretty much like credit transfer. I would encourage you to first apply and then go with the flow. Im Glad you are smart and already thinking ahead by capitalizing on your achievements.. GOOD LUCK!

Thank you Kichkanni for your reply. Do they ask for GMAT too? I am planning to apply next semester and universities I emailed have not replied yet.