After getting and seeing many requests for documentation on the basics of creating and working with extension objects, I decided to create some document to help. The intention of this document is to provide people information on how to get up and running with extension objects with their most common uses and settings. There are several references here to a template QAR extension, which is an extension I created that could be used as a good starting point to copy and paste in creating new extensions.
Extensions can get WAY more complicated than what is presented here, but I'd say this document covers what is needed to create a basic extension. If you have any ideas for improvement or things to add, feel free to send me a revised version of the document and I can update.