Prerequisites 

Composer

Composer is a tool for dependency management in PHP. It allows you to declare the dependent libraries your project needs and it will install them in your project for you.

• Install Composer

Configure your app 

The ideal .platform.app.yaml file will vary from project project, and you are free to customize yours as needed. It also varies somewhat from one Symfony version to the next as Symfony has evolved. See the appropriate repository below for your Symfony version.

• Symfony 3
• Symfony 4