Hi have a cash register sharp xe a 101 for a restaurant
i need to reprogram because i have never done it

i downloaded the user manual its really hard to understand please help me out,

I need to program 12% (for the food) under department key 1, and 2 and 3
i also need to program 12 % (for the liquor) under department key4.

i guess i have to program the department keys for that too please help asap!

Please give instructions how to do it exactly.