I wanted to install the Symfony 4 beta to play with the new features. While I was able to get most of it working, but was facing issues due to package dependency when trying to install some common bundles. I then settled with the 3.4 branch, which has the exact same functionalities except for some backward compatibility.
Here are the steps to get the framework up & running with the most used bundles:
composer create-project symfony/skeleton symfony "3.4.0-BETA1" cd symfony/ composer req web-server "3.4.0-BETA1" composer req annotations composer req orm composer req annotations composer req doctrine-migrations composer req debug "3.4.0-BETA1" composer req log composer req profiler composer req security "3.4.0-BETA1" composer req mailer composer req validation "3.4.0-BETA1" composer req encore composer req twig-extensions composer req serialization "3.4.0-BETA1" composer require friendsofsymfony/rest-bundle composer require stof/doctrine-extensions-bundle
Once the installation is done, you can start the application using the web server and it should be running.
You may want to follow the Symfony 4 blog series at http://fabien.potencier.org to get started as the official documentation is not updated yet.