The samples collection is a good starting point to get help. They provide a variety of practical use cases for the PDFNet SDK.

The PDFNet SDK forum is a great place to find answers to common problems. Feel free to look around and ask your own questions on the forum. There are plenty of answered questions, and chances are that your question has already been asked by somebody else.

Also included with your PDFTron SDK is a collection of samples that demonstrate most of the features available with PDFNet.

http://www.pdftron.com/pdfnet/samplecode.html

FAQ:http://www.pdftron.com/pdfnet/faq.html

Introduction:http://www.pdftron.com/pdfnet/intro.html

Documentation (API References):http://www.pdftron.com/pdfnet/documentation.html