I want to build an excel add-in which is application level. I followed the instructions to create a project on MSDN.
I don't want to create a COM add-in, I want an Excel plugin. The plugin we create as .xlam file and code it in VBA.
Please suggest me what to do. How to deploy the .vsto file and patch up with the .xlam file?
A VSTO Office add-in is a COM add-in by definition. That is how Microsoft implemented it. They have built a bridge from .NET to the native Microsoft Office code using COM.
If you want an XLAM add-in, as you say, you need to go through this reference, which doesn't involve creating a Visual Studio VSTO project.