Ionic 4, appflow & fastlane

Hello,

I try to customize the ios app id at compilation time (it’s based on a property file). For that, I saw that a fastlane plugin exists. So far, I haven’t configure fastlane. But I see that appflow setups it for me and uses gym to build the app. Can I customize the way appflow builds my app? is there a demo somewhere I can use?

Thank you,
Have a nice day,
Sébastien