To help you walk thru some of support we have added for sample data inside Blend 3, I wrote a hands-on-lab that takes you thru the basic experience of building a simple master/detail visualization. While there are a lot more scenarios that are possible with the support for sample data in Blend 3 (some of which are not available in the public preview build, and I will in write in detail about over the next few days), you can get a first-hand experience here for the following:

• A schema designer that allows you to quickly mockup a data source and supply values for the data
• Improved drag/drop experience to create bindings
• Master/Detail support in Blend 3
• Sample data that can be enabled/disabled when the application is running
• Optionally, if you are developer and are interested in knowing more about how things work behind the covers so you could adapt this for your scenarios, this can be a good starting point.

Download the hands-on-lab document here (because of the ISP that I use for hosting these files, you will have to rename this .zip file to .docx), and the starting project (to save you some time with the graphics, styling, and layout) here.