Umm,
Place drain pan under hose (Top of it if ya want to minimize fluid lost, but you are going to dump the whole radiator)
Disconnect top of hose, Slide slinky on.
Remove set screw from radiator cap, Top off with 50/50 mix.
idle to open the thermostat and get any excess air out (although there shouldn't be any)
Recap and check for leaks.
Be careful with the radiator cap as it and the fill hole can be easily damaged on removal/reinstall.
Did I miss anything guy's?
You could also rotate the slinky' first coil or two over the top clamp screw to hold it up high so it doesn't slouch if need be.