Recommend you deoil (basiclly nonsudsing detergent [bottle of SHOUT spot remover] ) first. It only adds two steps since you'll be decalcifing afterwards. ANY residual scum/petroleum will interefere with the decalcifying solution.
Removing the thermostat can speed things. HOWEVER, you can crack a block in a heart beat so be mindful of the flushing and filling.
Concur with previous posts about opening the black drain plug.
Unsolicited thoughts: Fill with your favorite Anti-Freeze. I'm a fan of Mercedes-Benz anti-freeze and distilled (de mineralized) water with Red-Line water wetter. Most go 50/50 but I don't live in extreme winter area so I reduce the antifreeze side of the mix per the info on the bottle. Water is a better heat transfer medium than antifreeze. For a few extra bucks spent on MB fluid, I worry less (it has their anticorrosion package, neutral pH (almost)...).
S, J.R. Brown
2000 G500 LWB Obsedian Black
2005 Toyota Tacoma Access Cab Off Road Sport
1993 Volvo 240 Sedan Anthracite
1980 450SEL Champange (owned it for 15 years. Great car)
1986 280GE LWB Anthracite (Sold it and kinda wish I hadn't)