Going to Costa Rica

Hey guys, Im borrowing my brothers unused Droid Pro phone. Ive read I can buy a SIM card and pre-paid card and make telephone calls, because it is an international phone.

My question is how do I set up my phone before we leave so it can accept the SIM & prepaid card. Should I activate the phone so it temporarily is my telephone number?

So please tell me if this is correct

1. Get phone

2. Activate Phone here in the US with my number/verizon account

3. Buy SIM Card & prepaid card

4. Register SIM card and prepaid card (or something)

Is this the right order? Im sorry, but Ive never done anything like this before. Thanks for your help again. Happy Holidays.