Hi,
I would not recommend starting with the "My First AutoCAD Plugin" tutorial.
This tutorial requires the use of "AutoCAD .NET Wizard" which is not always compatible with the versions of Visual Studio and AutoCAD used, while in my opinion it would be better to learn how to create a project for an AutoCAD plugin from scratch.
Moreover, this plugin is essentially based on Overrule, one of the most complex APIs in AutoCAD .NET.
I would advise to start with "AutoCAD.NET Training Labs" (on
this page) and only tackle "My First AutoCAD Plugin" once you have the basics.
EDIT: I had forgotten, in addition, "My First Plugin" is written in VB