//Merge the file. You can merge as many files
//as you would like here
EO.Pdf.PdfDocument result = 
    EO.Pdf.PdfDocument.Merge(
        new EO.Pdf.PdfDocument("c:\\1.pdf"), 
        new EO.Pdf.PdfDocument("c:\\2.pdf"));

//Add page number to each page
for (int i = 0; i < result.Pages.Count; i++)
{
    //Create an AcmText representing the page number
    EO.Pdf.Acm.AcmText text = 
        new EO.Pdf.Acm.AcmText("Page " + i.ToString());

    //Create an AcmRender to render the page number.
    //The arguments are:
    //First argument: the target page
    //Second argument: the "Y" position
    //Third argument: The paper margins in left, top, right, bottom order
    EO.Pdf.Acm.AcmRender render = new EO.Pdf.Acm.AcmRender(
        result.Pages[i], 10.5f, 
        new EO.Pdf.Acm.AcmPageLayout(
            new EO.Pdf.Acm.AcmPadding(1, 0, 1, 0)));
    render.Render(text);
}

//Render the page number
result.Save("c:\\3.pdf");

Dim result As EO.Pdf.PdfDocument

'Merge the file. You can merge as many files
'as you would like here
result = EO.Pdf.PdfDocument.Merge( _
    New EO.Pdf.PdfDocument("1.pdf"), _
    New EO.Pdf.PdfDocument("2.pdf"))

'Add page number to each page
For I As Integer = 0 To result.Pages.Count - 1
    Dim pageNumber As EO.Pdf.Acm.AcmText
    Dim acmRender As EO.Pdf.Acm.AcmRender

    'Create an AcmText representing the page number
    pageNumber = New EO.Pdf.Acm.AcmText("Page " + (I + 1).ToString())

    'Create an AcmRender to render the page number.
    'The arguments are:
    ' First argument: the target page
    ' Second argument: the "Y" position
    ' Third argument: The paper margins in left, top, right, bottom order
    acmRender = New EO.Pdf.Acm.AcmRender(result.Pages(I), 10.5, _
        New EO.Pdf.Acm.AcmPageLayout( _
            New EO.Pdf.Acm.AcmPadding(1, 0, 1, 0)))

    'Render the page number
    acmRender.Render(pageNumber)
Next

'Save the result file
result.Save("result.pdf")