Set all the high rates on the radio to be 100%. The radio is most accurate and the servos most accurate when the radio is working at 100%. Then set your surface throws on the airplane with the servo arm, pushrod, and horn to give you whatever throw the manual suggests for high rates.

Pretty simple so far. And easy to do.

Then setup each function in the radio to whatever percentage gives the low rate throw recommended by the manual.

As for expo..... If you've never used it before, try something like +30 for JRs and -30 for Futabas. And you set it for each surface at each rate setting for most of the better radios.