My colleague Adam Nagy had created an nice video recording back in 2008 on "Introduction to RealDWG .Net programming". You can download the recording here
DevTV on RealDWG programmingHere is another recording with the same sample project. The changes are mainly in the installer creation and in the licensing steps which have changed since the last recording was created.
The sample project and the slides can be downloaded here :
SampleCode_DevTV