JMC Gold 2250 Register- need to program the discount key to 10%?

I tried the manual A-J--DISC--#/NS and when I hit DISC key it just beeps with the E at the front of my number code. I need to program a key that can give me a 10% discount, not allow multiple subtl discounts, before subtotal, before tax, rounding code 5(rounding up or down).