Sub ImportMonthlySales()

    Dim myTextFile As Workbook
    Dim OpenFiles() As Variant
    
    OpenFiles = GetFiles()
    Application.ScreenUpdating = False
    
    For i = 1 To Application.CountA(OpenFiles)
        Set myTextFile = Workbooks.Open(OpenFiles(i))
        
        myTextFile.Sheets(1).Range("A1").CurrentRegion.Copy
        Workbooks(1).Activate
        Workbooks(1).Worksheets.Add
        ActiveSheet.Paste
        Application.CutCopyMode = False
        myTextFile.Close
    Next i
    
    Application.ScreenUpdating = True
    
End Sub
 
Private Function GetFiles() As Variant
    
GetFiles = Application.GetOpenFilename(Title:="Select File(s) to import", MultiSelect:=True)
 
End Function