I made a QuickPart to Normal.dotm and now I want to place it to the document
(where the cursor is) using C# interop. The basics (create application, create document, locate cursor etc.) doesn't need to be covered, I know those, but how does the beef of that work like?

Here's the same as "pseudocode"
Word.Document ActiveDoc = Globals.ThisAddIn.Application.ActiveDocument;
Word.Selection selected = Globals.ThisAddIn.Application.Selection;
Word.Range rng = selected.Range;


rng.AddQuickPart("Normal.dotm", "ThePartIJustCreated"); //This one obviously doesn't work

Found it:


private static BuildingBlock GetQuickPartFromTemplate(Microsoft.Office.Interop. Word.Application wordApplication, string wordTemplateDocumentPath, object quickPartName)
{
return (from Template template in wordApplication.Templates
where template.FullName.Contains(Path.GetFileNameWithout Extension(wordTemplateDocumentPath))
let index = quickPartName
select template.BuildingBlockEntries.Item(ref quickPartName)).FirstOrDefault();
}

https://stackoverflow.com/questions/...s-using-c-shar

You can call it like:
string temp = Environment.GetFolderPath(Environment.SpecialFolde r.ApplicationData) + @"\Microsoft\Templates";
BuildingBlock b = GetQuickPartFromTemplate(doc.Application, temp + "\\Normal.dotm", "ThePartIJustCreated");

Range rng = doc.Application.Selection.Range;
rng = b.Insert(rng);