The following reading material will provide you with more information about Angular feature modules/core modules/shared modules, routers, lazy loading, and animations:
- Feature modules: https://angular.io/guide/feature-modules.
- Shared modules: https://angular.io/guide/sharing-ngmodules.
- Singleton services: https://angular.io/guide/singleton-services.
- Angular Router: https://angular.io/guide/router.
- Angular animations: https://angular.io/guide/animations.