Which target?
Most salt chlorine generators want roughly 2,700–3,400 ppm; use the number in your cell’s manual, because running too low wears the cell faster and too high can trigger errors or corrosion. Salt test strips and the cell’s own reading often disagree; a good drop-test or a calibrated meter settles it.
Adding salt
Use pool salt (at least 99% sodium chloride, no anti-caking agents like yellow prussiate of soda or iodine). Turn the generator off, pour salt into the deep end, brush it around and run the pump for 24 hours before turning the cell back on.
Not professional advice. Results are estimates for residential pools and hot tubs. Read and follow product labels: add chemicals separately, to water (never water to chemicals), with the pump running, and retest before adding more. Commercial and public pools must follow local health codes.