To locate it definitively:
1. Consult your owner's manual: This is the best source of information for your specific vehicle. It will show a diagram of the cooling system and clearly identify the drain plug.
2. Look carefully at the bottom of the radiator: Once you've located the radiator (it's the large, rectangular component at the front of the engine bay), inspect the bottom carefully. The drain plug will be near the bottom, usually towards the driver's side. It may be slightly recessed.
3. Look for a small, threaded plug: The plug is likely to be smaller than other bolts or connections in the area.
Caution: When draining the radiator, be sure to have a suitable container ready to catch the coolant. Coolant is toxic and should be disposed of properly according to local regulations. Also, be aware that the coolant will be hot if the engine has recently been running, so allow it to cool down before attempting to drain it.