Tkinter OOP organizing widget on a class which inherits from tk.Toplevel

I have organized my GUI with a parent app class which inherits from tk.Frame. In the main main app I create a top level window object which is a pop up when a button is pressed. This class inherits from tk.Toplevel. The Toplevel should have its own widgets which need to be organized neatly. I am wondering what is the best way to organize the widgets on the Toplevel. Below is the code which shows the overall structure of the GUI I am trying to write. The submit_button class is where widgets need to be organized properly.

import tkinter as tk
from tkinter import ttk

class Window(tk.Frame):

   def __init__(self, master=None):
    
      tk.Frame.__init__(self, master)
    
      self.title = "TITLE"
    
      self.master = master
    
      self.submit = ttk.Button(self, text = 'SUBMIT', command = self.click_submit_button)
      self.submit.grid(row = 0, column = 2, padx = 20, pady = 20)
    
  def click_submit_button(self):
    
      self.submit_pop_up = submit_button(self.master)
    
    
class submit_button(tk.Toplevel):

  def __init__(self, master):
    
      tk.Toplevel.__init__(self, master)
    
      self.master = master
    
      self.title = 'TITLE'

if __name__ == "__main__":

  root = tk.Tk()

  app = Window(root)

  app.pack()

  root.mainloop()