Thorough instructions are coming soon. In the meantime, try using Vagrant, or start your own quest:
You need rvm, or another way of installing Ruby 1.9.3 and creating an isolated $GEM_HOME. You need git, so you can push/pull changes. You need PostgreSQL.
See UBUNTU_SETUP.md and OSX_SETUP.md for detailed instructions that you may be able to adapt to Windows.