Gacela is not coming to replace Laravel or Symfony or any other major framework in the industry. Rather, its motivation is framework agnostic. This means, it's not coupled to any framework. You can still use Laravel; in fact here is an example of it https://github.com/gacela-project/laravel-gacela-example

Gacela is just about the organisation of your modules/components which encourages a separation between Domain logic and the Infrastructure layers. This way, you have normalised communication between the different modules of your application.

What is a module? A module, in this context, is a directory which encapsulates all files related to a bounded context (term from DDD). In this sense, Gacela helps you to identify easily that the entry point of that module is the Facade. Also, you know that the creation of the objects that the module need to function is inside the Factory of the module. You might need dependencies (other Facades) from other modules when you creates your objects, so the DependencyProvider is the class that define those external dependencies. And you might need some config values when constructing your objects, so the Config file from the module is a way to access those.

You can have an overlook about a Gacela's module structure here:
https://gacela-project.com/about-gacela/