To transfer a project to Symfony, you first need to upload the files to the server. This can be done in several ways:
git clone http://github.com/example/example_site/
After uploading files to the server connect over SSH and do the following:
PATH=/usr/local/php70/bin:/usr/local/bin:/bin:/usr/bin:/usr/local/sbin:/usr/sbin:/sbin composer update
.env, then you may need to run the command:
composer require symfony/dotenv
APP_ENV=prod APP_DEBUG=0 php bin/console cache:clear
bin/console doctrine:schema:update --force
More information can be found in documentation.
After completing these steps, additional steps may be required to customize the project. In this case, you should contact the project developer to clarify more detailed information.