doc, read the % of cl on the lable if 5% use 3/4 cup to a gallon of water.
adjust if it's 4 %, by reducing the gallon (128 oz) 20% ( to approx 100 oz)
always add the clorox to the water.
If you can find pool chlorine it's 10 % use 3/4 cup to 2 gallons water.
Keep the mixture in a cool dark place tightly capped.
Don't store it in a spray bottle unless it's for use with caustic materials i.e. chemical resistant.