Thank you for giving a try to the new GroupDocs.Viewer.
Please note that the new GroupDocs.Viewer is a UI-less API exposing only UI-less+back end document rendering APIs thus enabling you to use APIs in a larger number of scenarios without worrying about application development platforms. Therefore, you may not use the new version in the way as you were using previously. Please feel free to have a look at the migration article: http://groupdocs.com/docs/display/viewernet/Migrating+to+GroupDocs.Viewer+3.0.0+or+Greater
For complete docs and examples, please go through below resources:
In case, you have problems using the new GroupDocs.Viewer, please create a new thread with some proper user account instead of posting as “Anonymous” so we can keep track of your problems. Thanks for your understanding and cooperation.