@Anonymous
I have some advice from my own experience. I'm new to this, have never done any programming before, and are currently working on an Add-In using Visual Studio in VB .net as a side project on my spare time.
I started out with the Add-In template as you did, adding Modules & Classes to contain the code for my application. I have found myself really appreciating all the good work put into the Inventor API Help. Without it, I probably would have given up a long time ago. There is a lot of useful information in the User Manual chapter to get you started. But I frequently use it to point me in the right direction to achieve what I plan to do.
Regarding the reason for why you abandoned your project in the past: If you add Inventor to the project in Visual Studio as the Debugging application, you can Debug directly in Visual Studio which automatically launches Inventor. Doing this automatically adds the files (.dll ++) to the correct location on your computer, so you are also able to launch Inventor separately (without Visual Studio) and use the Add-In as normal.
I believe this is stated in the previously mentioned chapter in the API Help, so that's what I've done, and it works like a charm.
For deployment to other computers, then you should refer to the API Help for where to unpack/copy the files. (see picture below).


I also highly recommend watching the following video by the API guru Brian Ekins, detailing VBA vs iLogic vs VB.NET and more:
http://au.autodesk.com/au-online/classes-on-demand/class-catalog/classes/year-2016/inventor-professional/sd17917#chapter=0
Hope that helps a little.