To run:

• symfony server:start

Don't forget:

• composer install
• You'll need composer installed and in your global path
• You'll need symfony local webserver globally

More on prerequisites: https://symfony.com/doc/current/setup.html

Example ~/.bash_profile:

export PATH="$HOME/.symfony/bin:$PATH" 
export PATH="$HOME/.composer/bin:$PATH"

In this case ~/.composer/bin contains composer.phar renamed to composer. Close and re-open bash terminal after editing this file.