To be sure, you should:
* Consult your owner's manual: This is the best resource for the exact location and instructions.
* Look carefully at the bottom of the radiator: It's usually low and toward the front on the driver's side, but check both sides just in case.
* Feel around the bottom of the radiator: The drain plug will often be a slightly different texture or protrude slightly from the radiator.
Important Safety Note: Before draining the radiator, allow the engine to cool completely to prevent burns. Have a suitable container ready to catch the coolant. Coolant is toxic, so handle it appropriately.