Never cooked curry before.  This makes it so simple.  I just follow the directions.  You need to experiment with the amount you use for the amount of heat you want.  I use a heaping table spoon (silverware, not a measuring spoon) of the curry paste for one standard size can of coconut milk, and about a pound of meat or shrimp.  It's hot, but not crazy hot.  I tried 2 heaping tbl spoons the last batch, and it was way too hot for me.