How to add more mav_x_config options to configure external peripherals?

Hi,
I am currently working with PX4 and I need to configure more external peripherals using the MAVLink configuration system. However, I am unsure how to add additional mav_x_config parameters for custom peripherals.

Could someone guide me on how to add more configuration options in the MAVLink system? Specifically, I would like to know the steps to create new mav_x_config parameters and how to manage them within the PX4 software.

Any advice or pointers to documentation would be appreciated. Thank you!