Hi,
If you are new to ASP.NET development, I suggest you get a good book about it. Its very important to understand the lifecycle of events in pages and controls during a web request.
I also recommend you use the mojoportal source code package with Visual Studio 2008 SP1 or Visual Web Developer Express 2008 SP1, and use the mojoportal.sln solution file.
The best way to learn is to study existing code and mojoportal has exisiting code to do almost any kind of development task you need to learn like accessing databases and other common development tasks. So the source code is the very best documentation available.
Other documentation is available here:
http://www.mojoportal.com/documentation.aspx
http://www.mojoportal.com/developerdocs.aspx
Hope it helps,
Joe