I want to add Chlorine to my large kiddie pool?

they say 1 teaspoon per 4 gallons. so divide 264/4 and put that many teaspoons in. if i were u, id convert teaspoons into a larger measurement! lol

Your gallons are off. If your measurements are right, you have 110 cubic feet of water in your pool, which equates to roughly 822 gallons. 264 gallons would be a 6' by 3' by 2' deep. Although it would be best for you to get accurate numbers to determine how much chlorine to add, with that small of a pool, it probably doesn't make sense to spend more than $40 on a testing kit. If the 264 gallons is correct, to bring your free chlorine level up to 3 ppm, I'd add 2 oz (1/4 cup) of unscented household bleach. Add around 4 oz of liquid stabilizer (cyanuric acid) to keep the sun from burning the chlorine off, or put 1.5 oz of the granular stuff in an old sock and swirl it around (keeps it from damaging your pool). If 822 gallons is closer to your capacity, add about 6 oz of bleach. Add around 11 oz of liquid stabilizer, or 5 oz the granular stuff. Either way, that will bring up your free chlorine level to where algae and bacteria will be killed. Note: only add the CYA once. It stays in the water.