You don’t need to touch your source code at all.
Localazy works fully automatically and select the best matching locale based on the user settings.
It uses the same detection mechanism as Android.
The Localazy library allows to switch locales manually if you want to use it, but it’s not required.
If you, for some reason, need to work with locales manually, see the documentation for Localazy Android library:
https://localazy.com/docs/android/localazy-android-library#working-with-locales