Dear Israel,
please see below an answer from an application engineer I have contacted.
DESCRIPTION
The RF block is initialized in the u8InitRf() function located in main.c
This is where the registers controlling the frequency, baud rate, frequency deviation… are configured.

To see the correspondence between register values and frequency, baud rate… please refer to the user manual which details all registers:
https://www.nxp.com/webapp/Download?colCode=UM11227&appType=license
With Best Regards,
Jozef