Getting Started:

https://shapeshift.readme.io/reference/getting-started-with-your-api

https://exchange.shapeshift.com/

Pre-FAQ:

https://docs.google.com/document/d/1TNhZa_XUWRF48HO4WAF_-bCH9Rsbg_VEQtBJK6yfjVk/edit?usp=sharing