You need 2 gallon of straight coolant, NOT 50/50 premix.
See my Cave, Coolant Fill
Two plugs on the lower pipes and "plug" on radiator.
If flushing, can just drain the pipes and that will drain most of the rest w/o getting under the car.
Most DIY can Install flush kit from Prestone et al and follow kit's directions but Radiator "outlet pipe" often doesn't work on Fiero.
Drain most of water after then fill as directions in my Cave.
If coolant get on electrical parts, clean them before turning on. Coolant is very conductive and can short out many things.
Most Engines have drains but don't bother them.
Pipe drains are not SS and can rust etc. Plus is Not metric pipe fitting but rust/wear can make metric allens to work better. Use a small straight screw driver etc to clean the plugs before trying to remove them.
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
The Ogre's Fiero Cave