What is the right way to put configuration file for my package?

I use this config https://github.com/VictoriaMetrics/VictoriaMetrics/blob/master/snap/snapcraft.yaml#L83 as example for new packages, but this file is empty and my application can’t start without properly configuration. Can somebody point me to url with example of creation the new config file while running build or create the new one after start? Thanks!