Let's use Terraform to easily get a CoreOS cluster up on Digital Ocean. In this example we will get a 5 node CoreOS cluster up and running on the Digital Ocean 8GB size.
Grab a copy of Terraform for your platform from http://www.terraform.io/downloads.html. Follow the instructions at http://www.terraform.io/intro/getting-started/install.html by getting Terraform in your PATH and testing that it works.