mapper is for games that have on screen controls.
emulators have a "input" menu option that allow to you to remap your keys to the game.
open the emulator, go to input (o equivalent) option, uncheck "auto config" (or similar, if there is any option like this)
go to "custom binds", "key assign", "key map", etc (any similar option)
then, you will get a list of actions similar to:
select each of these options and the program will wait for some inputo from your device.
press "DPAD UP", and when the program prompts, press the DPAD UP button.
this is the general mechanic for mapping on emulators (take note, emulators usually have this option. android games not)