On the IB website you can find an email address, I think under 'legalization'. You contact B, they send you back an answer describing the process of legalization, the amount of money you have to pay for all this, and the address where you should send the original IB diploma. There were some problem with mine and it took a bit longer that ussual, bt from I remember it takes 2-4 weeks from the date they receive your diploma.