OpenSpan and Pega Robotics Studio are synonymous words here. If you are looking for documentation on Pega 7 integration with Studio, we currently only have documentation on how you might do some tasks. These documents can be found on the OpenSpan Support site.
Pega Robotics is OpenSpan Studio with added features that allow seamless integration with the Pega 7 platform. If you are looking to understand the core functionality of the product, then reviewing the lesson plans and exercises for OpenSpan Studio should suffice.
There is no user guide for Pega Robotic Automation Studio and Runtime, instead there is an extensive Help system that should answer most of your questions. You can access this Help system from the Robotic Automation landing page on the PDN.
On the landing page, you will also find links to other Studio and Runtime related documentation, such as the Deployment Portal User guide, the Agile Desktop Implementation Guide, the Updater Implementation Guide, and so on.