How do i change the radiator fluid?

Most radiators have a drain plug on the bottom tank the engine block also has a drain plug . Remove the radiator cap ,open both drains ,let all the coolant run out, if there is no radiator plug remove the lower hose , remove the heater demister hoses, with the heater control on hot flush out all the coolant from the heater radiator. with a garden hose, till the water runs clean, tighten the radiator plug or re fit the hose,put a garden hose into the radiator and flush out till the water at the block plug runs clean ,refit the heater hoses, refit the block plug, fill the radiator from the hose leave the cap off , If it has a overflow tank clean and flush it. start and run engine for 5 minutes top up radiator if needed . stop engine and drain out all water. most important that all old coolant is drained out, only buy the best coolant you can . If you make up your own use only distilled water. keep some to top up with never mix with another brand. Fill radiator with coolant top up over flow tank, run engine top up coolant as needed, refit radiator cap run for another 10 minutes check for leaks,