Install mageto witgh sample data using composer

1) install composer

2) composer create-project --repository-url=https://repo.magento.com/ magento/project-community-edition golfstylesforless

When prompted, enter your authentication keys. Your public key is your username; your private key is your password.

3) from browser, run htpp://localhost/projectname/setup

4) install sample db :
php bin/magento sampledata:deploy
php bin/magento setup:upgrade

php -dmemory_limit=6G bin/magento setup:upgrade