Talend is a powerful data integration opensource software.
The offical website includes a section with some clear, printscreened tutorials that let you explore the major functionalities.
The PDF documentations: user and components reference guide (in french and english) are really complete.
In the components reference guide, you'll find scenarios for each component.
Also, some webinars are animated live during which some Talend users from different organizations (public, private) explain how they use Talend. The webinars are still accessible in the webinar archives part.
Like for every software, the best thing is to practice. To approach all the software's potentials or even to figure out what could be processed, case studies are really helpful. So, it's a good news Talend published a case studies PDF. You'll probably find it useful to see how organizations used Talend in some ambitious business intelligence projects where data integration and orchestration were some prerequisites.