StartNumber

public int StartNumber { get; set; }

Document doc = new Document();
DocumentBuilder builder = new DocumentBuilder(doc);

// Footnotes and endnotes are a way to attach a reference or a side comment to text
// that does not interfere with the main body text's flow. 
// Inserting a footnote/endnote adds a small superscript reference symbol
// at the main body text where we insert the footnote/endnote.
// Each footnote/endnote also creates an entry, which consists of a symbol
// that matches the reference symbol in the main body text.
// The reference text that we pass to the document builder's "InsertEndnote" method.
// Footnote entries, by default, show up at the bottom of each page that contains
// their reference symbols, and endnotes show up at the end of the document.
builder.Write("Text 1. ");
builder.InsertFootnote(FootnoteType.Footnote, "Footnote 1.");
builder.Write("Text 2. ");
builder.InsertFootnote(FootnoteType.Footnote, "Footnote 2.");
builder.Write("Text 3. ");
builder.InsertFootnote(FootnoteType.Footnote, "Footnote 3.");

builder.InsertParagraph();

builder.Write("Text 1. ");
builder.InsertFootnote(FootnoteType.Endnote, "Endnote 1.");
builder.Write("Text 2. ");
builder.InsertFootnote(FootnoteType.Endnote, "Endnote 2.");
builder.Write("Text 3. ");
builder.InsertFootnote(FootnoteType.Endnote, "Endnote 3.");

// By default, the reference symbol for each footnote and endnote is its index
// among all the document's footnotes/endnotes. Each document maintains separate counts
// for footnotes and for endnotes, which both begin at 1.
Assert.AreEqual(1, doc.FootnoteOptions.StartNumber);
Assert.AreEqual(1, doc.EndnoteOptions.StartNumber);

// We can use the "StartNumber" property to get the document to
// begin a footnote or endnote count at a different number.
doc.EndnoteOptions.NumberStyle = NumberStyle.Arabic;
doc.EndnoteOptions.StartNumber = 50;

doc.Save(ArtifactsDir + "InlineStory.StartNumber.docx");