Do you currently have Toyota Red Coolant in your car, or has somebody put green stuff in at some point?
If you have red already, and no signs of rusty water, then its just a case of draining it all out via the drain on the bottom of the radiator, and the petcock on the side of the block, then do them up and refill with the correct ratio of coolant and water, then burp the system to ensure no air bubbles are trapped.
Now would be a goof time to consider replacing any old hoses or the thermostat etc, as when the system is drained, its easist time to do it