Excelファイルを新規で開く処理です。
ExcelのBookが1つ起動します。
' Excelアプリケーション
Private xlApp As Application = Nothing
' ワークブック
Private xlBooks As Workbooks = Nothing
Private xlBook As Workbook = Nothing
xlApp = New Application
xlBooks = xlApp.Workbooks
xlBook = xlBooks.Add