Where is the radiator drain plug on a Peugeot 406?

i have just bought a Peugeot 406 lx diesel ]1996] and need to put anti freeze in the rad, but the system is filled to top with water. How do i drain the system and where is the radiator drain plug?

when the engine is cold pull the bottom rad. hose off at the rad. and run the engine with a water hose in the filler cap until every thing clears up stop the water shut it down and let it drain as long as it will . put it back together put the anti freeze in first and fill it up then run it until its warmed up and make sure its full and have the heater on for all of this.