Depending on the vehicle it should hold a gallon and a half to two gallons, refer to your owners manual for exact amount.
In the coolant reservoir when the engine is cool.
you can use as much as you like as it makes the car run cooler
It should be a 50/50 mixture of water and antifreeze.
All the time
some people have said you should and others have said you dont have to. I myself have never put antifreeze in the during installation in all the years i have worked on cars
50 / 50 mixture of antifreeze and preferably distilled water usually ( Ford says not to have less than 40 % antifreeze and not more than 60 % antifreeze )
You'll usually see a "Fill Line" on the reservoir bottle, fill it to there.
You should use a gallon of coolant.
50/50 mixture.
As long as the engine didn't overheat you should be O.K.
the antifreeze runs through all your water lines in your car . . . . you put it in your water tank or radiator
If your vehicle seems to be having problems try to add the anti-freeze as soon as possible. If you don't use your vehicle much it can wait for when you have time.