How to change name on the receipt and reprogram dept keys?

Hi i have a Samsung ER-4915 cash register. I bought second hand. Im needing to change the name of there old business to ours and in my manual im going by what they say to do but having problems. I have a void, reg,x,z, and a p. key will not turn into the p setting. i tryed 37 x/time 1 sub total and the E1 buzzes. How do i change the name and reprogram dept. Thank you