Read the bottle. I bet it says that you're SUPPOSED to mix it 50/50 with water. I'm just going by the pictures you posted above, that's the same stuff you can buy in any Kmart... Prestone does sell some stuff that's already mixed, but it says so on the bottle.

When you drain your radiator it never ALL comes out. So after rinsing & draining you've still got a quart(?) of plain water in there. Find out how much total capacity in the cooling system, 7.3 quarts in my '98 4-cyl. Just add half of that (almost a gallon) from the antifreeze bottle. Then add water until it's full. Simple.