Insert Paragraph in a desired space of opened document

I attached a pic described a task. Already have a file with 2 paragraphs, need insert third paragraph between them. Can I do it via docbuilder language? I tried lines like this:

let nElementsCount = oDocument.GetElementsCount();
var oParagraph = Api.CreateParagraph();
oParagraph.AddText(nElementsCount);

By this I wanted 1) get a count of elements 2) insert element between them. In a step (1) I expected to see “2” (2 paragraphs), but there is no return by these lines.