To add multiple upload control and set up handler for it is quite easy in Visual Studio 2013. 

Add web.form page to your project, for example "Default.aspx" and add between "<form id="form1" runat="server"> <div>" and "</div></form>" this code:

  <h1>Upload Multiple Files</h1> 
        <asp:FileUpload ID="fileUpload1" AllowMultiple="true" runat="server" /> 
        <br /> 
        <asp:Button ID="btn" runat="server" Text="Upload" OnClick="btn_Click" />

In codebehind add this:

using System.IO;
.....

    protected void btn_Click(object sender, EventArgs e) 
    { 
        HttpFileCollection fileCollection = Request.Files; 
        for (int i = 0; i < fileCollection.Count; i++) 
        { 
            HttpPostedFile uplFile = fileCollection[i]; 
            string fileName = Path.GetFileName(uplFile.FileName); 

            if (uplFile.ContentLength > 0) 
            { 
                uplFile.SaveAs(Server.MapPath("~/Files/") + fileName); 
            } 
        } 
    }