that prestone flush stuff is handy if its got gummed up dex, its like a detergent.
this video gives ya basics, nothing specific but its kinda handy
if youre worried and not afraid to spend a few extra bucks, buy premix, but its almost fool proof,
Bleeding is the key element, and it will bleed itself a little over first few days of driving.
also take and maybe change the thermostat, and flush the lim seperately with water, same as heater core, dex loves to hide there.