#!/bin/python3

import tkinter as tk

#root application, can only have one of these.
root = tk.Tk() 

#put a label in the root to identify the window.
label1 = tk.Label(root, text="""this is root
closing this window will shut down app""")
label1.pack()

#you can make as many Toplevels as you like
extra_window = tk.Toplevel(root)
label2 = tk.Label(extra_window, text="""this is extra_window
closing this will not affect root""")
label2.pack()

root.mainloop()