The best way to learn something is practicing so it is how we will understand these patterns.
First to install the dependencies run
composer install
This will install the Symfony console.
php bin/console MonkeyCoders:DecoratorFastFood
php bin/console MonkeyCoders:DecoratorFigures
php bin/console MonkeyCoders:AdapterPaymentGateway
php bin/console MonkeyCoders:TemplateMethodHamburguer
php bin/console MonkeyCoders:ChainOfResponsibilityHamburguer
php bin/console MonkeyCoders:ObserverSignUp