install symfony from composer code example
Example 1: symfony install website skeleton
# run this if you are building a traditional web application
composer create-project symfony/website-skeleton my_project_name
Example 2: symfony new project
# use the most recent LTS version
$ symfony new my_project_name --version=lts
# use the 'next' Symfony version to be released (still in development)
$ symfony new my_project_name --version=next
# you can also select an exact specific Symfony version
$ symfony new my_project_name --version=4.4
# The --full option installs all the packages that you usually need to build web applications.