if the coolant wasn't contaminated with oil/rust/muck and is up for its 2yr change:
-wait for system to cool till luke warm
-turn heater to hot to open the heater matrix valve
-remove rad cap
-remove front undertray below radiator if fitted
-jacking the front up may help access if suspensions been lowered alot but most cases its not needed
-place container under radiator
-loosen and disconnect lower coolant pipe from radiator, drain all coolant into tray. syphon coolant out of the expansion tank if you can be bothered but its not important
-reconnect lower pipe onto radiator, replace the clamp if too rusty
-mix 50/50 coolant/water in a bucket or ratioed to the season
-fill expansion tank to full
-slowly pour new coolant into the rad till its full then help purge out the bubbles by squeezing away at the top coolant pipe till no more bubbles emerge
-remove air from the expansion tank u-pipe (squeeze top pipe, cover rad port with palm, release top pipe to suck air/coolant through the pipe, repeat 3x and topup tank if needed)
-leave rad cap off and heater on hot
-start engine and either let it idle (takes longer to warm up) or rev to 2k till the fan has turned on & off. this allows the thermostat to open at 82c letting any bubbles out before the fan kicks in
-while warming up, the coolant level at the rad port will begin to expand too high. simply cover the rad port with palm, squeeze the top pipe to push the excess into the tank, remove palm and release top pipe
-turn engine off, fit rad cap, turn heater to cold, let engine cool down and check the coolant level
if the coolant was dirty, the remaining coolant in the engine and radiator will need flushing with a garden hose