where to find those function files when I open demo project ' ADC_OneShot-Debug’ source code ?

Hi Guys, I’m learning programming for RL78/G13. I use ‘Demo Kit for RL78G13’ ( PN: YRDKRL78G13). After install ‘IAR Embedded workbench IDE’, I can open the project of ‘ADC_OneShot-Debug’. I move down the mouse and open the Applilet Code, and then saw all source code ( .c file and .h file) there. I open r_main.c to read.

My question is that, some function files which appear in the r_main.c ( e.g. InitialiseDisplay() ) have no where to find !!   can anyone tell me where to find those function files?  very appreciate!