I seem cannot find by search in internet and in books on SPD any explanations (step-by-step, tutorial, walkthrough) on:
- How to use "Get Parameters From" of "Web Part Connection Wizard" (SPD 2010)?
Below links will help you get started. Although there many good examples present in SharePoint Designer books you may find in Wrox and Apress publication but these are quick and effective tutorials on this topic.
Microsoft SPD working with Webpart connections- Video
SharePoint 2010 Parent/Child List Relationship
Walkthrough exerpt from Beginning SharePoint Designer 2010 Book http://my.safaribooksonline.com/book/operating-systems-and-server-administration/microsoft-sharepoint/9780470643167/web-part-connections/creating_a_composite_user_interface