Before you can decide what needs to be added,(other than stabilizer, you know you need that ) you have to know where your starting levels are. Test for all of them, come back and post them here, and add enough chlorine (I would start with bleach til we know what else your water contains) to get to 3-6 ppm. I would not start using trichlor until we know what your pH level is.

Be prepared to add more chlorine 2-3 times a day until you get some stabilizer in the water.