Search for GitLab CE X.Y (X.Y represent version number) or GitLab EE X.Y under Community AMIs. The latest version of GitLab CE/EE will be fetched on first boot.
Launch a c4.large instance with open ports for ssh, http and https.
SSH into the instance with ubuntu@your-instance, edit the
/etc/gitlab/gitlab.rb file to your needs, and run
sudo gitlab-ctl reconfigure
Visit the public IP in a browser and sign in as the default user