I have always found ways NOT to create my own super-awsome Manifold add-in. When I have tried to create one for practice, there are often some silly noob mistake in addin xml or wherever that ruins the experience. So I created a Visual Studio template for Manifold add-ins that contains all the necessary files and an install_MyAddin.bat file that puts them in right place. I have used samples from other forum members to get started and I'm grateful.
What's it for?
This template gets you started with Manifold GIS Add-Ins. It helps you to avoid many common mistakes along the way.
1. Download zip [link] and put it into your Visual Studio Project Templates directory %userprofile%\Documents\Visual Studio 2015\Templates\ProjectTemplates
2. Unblock the zip file.
3. Create a new project in Visual Studio with this new template that should appear under Visual C#. Pick a name for your add-in and click OK.
4. After successful project creation you can build the project without modifying anything.
5. Browse to projectdirectory\bin\Debug directory. Run install_projectname.bat. It copies required files into Manifold's Config directory. NB! You have to have permission to modify Config directory.
6. Start a fresh Manifold. Go to Tools->Add-Ins. Your add-in shuld be listed there. Click on the name.
7. A new pane with silly text and projectname should appear.
8. If problem occurs, let me know.
Read The Fine Manual for more information about Manifold Add-Ins!