How do i change the coolant on a 05 impala please can someone help???

On the DEX COOL coolant that i bought it says to drain the cooling system exactly what does that mean and how do i do it? if anyone can help asap itll be appreciated thank you!!!!!!!!!!!!How do i change the coolant on a 05 impala please can someone help???At the bottom corner of your radiator tank is a drain valve. Drain the coolant, close the drain and refill. Idle the vehicle with the heater on low and add coolant as the air bubbles work themselves out.How do i change the coolant on a 05 impala please can someone help???There is a drain on the bottom of the radiator, make sure after you do this you bleed the coolant system after you fill it or it will overheat.How do i change the coolant on a 05 impala please can someone help???remove the drian plug from radiator,drain coolant reinstall plug. fill cooling system. bleed air from system. install cap drive vehicleHow do i change the coolant on a 05 impala please can someone help???look at the bottom corner of the radiator,there is a plug that you will turn counterclockwise.remove cap on rad,open the bottom and antifreeze will drain into the pan you use to catch the used coolant.once empty,close the valve at the bottom of rad,mix antifreeze 50/50 with water,fill radiator or catch tank start car and let run with the heater on high with fan on high.let get to operating temp and the fans have cycled.check the fluid is full put cap on and your good to go.