set Tkinter label widget below entry widget
<p>I am relatively new to Tkinter and I am trying to create a GUI with three horizontally aligned entry widgets and three corresponding label widgets. I am struggling with how to put the label widgets below the entry widgets without disturbing the alignment of the entry boxes (i.e., pack side = LEFT). Here is an example snapshot of the GUI without the labels below the entry boxes: </p>

<p><a href="https://i.stack.imgur.com/t13hl.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/t13hl.png" alt="enter image description here"></a>  </p>

<p>Currently my script looks like this, with the label widgets commented out:</p>

<pre><code>#!/usr/bin/python

from sys import exit
from Tkinter import *
from subprocess import Popen, PIPE
from time import sleep
from os.path import exists
import os
import time
import sys
import ttk

#Initialize Tkinter by creating Tk root widget, which is a window with a
title bar. The root widget has to be created before any other widgets.

Root = Tk()
Root.title("GUI")

class Command:
    def __init__(self, func, *args, **kw):
        self.func = func
        self.args = args
        self.kw = kw
    def __call__(self, *args, **kw):
        args = self.args+args
        kw.update(self.kw)
        self.func(*args, **kw)

 #Script definitions#

 def quitter():
    exit(0)


#Button organization and layout#


Sub0 = Frame(Root)
Sub = Frame(Sub0)

#X mesh node
Label(Sub, text = "Create x mesh nodes").pack(side = TOP, pady = 5)

#x min text box area
v1=StringVar()
#Create entry widge to get user input, in this case a text string for the x      
min mesh

Entry(Sub, textvariable=v1).pack(side = LEFT, pady = 5, padx = 5)
#Label(Sub, text = "min").pack(side = BOTTOM, pady = 5, padx = 5)


#x max text box area
v2=StringVar()
Entry(Sub, textvariable=v2).pack(side = LEFT, pady = 5, padx = 5)
#Label(Sub, text = "max").pack(side = BOTTOM, pady = 1)

#x step text box area
v3=StringVar()
Entry(Sub, textvariable=v3).pack(side = LEFT, pady = 5, padx = 5)
#Label(Sub, text = "step increment").pack(side = LEFT, pady = 1)

Sub.pack(side = TOP)
Frame(Sub0,height=1, relief = GROOVE, bg="black").pack(side = TOP, fill = 
BOTH, pady= 5)


#GUI Organization#


Sub0.pack(side = TOP, padx = 10)

Button(Root, text = "Quit", command = quitter).pack(side = TOP, pady = 5)

#The window will not appear until we enter the Tkinter event loop. Script
will remain in the event loop until we close the window.

Root.mainloop()
</code></pre>

<p>When I uncomment the label widgets I get the following: </p>

<p><a href="https://i.stack.imgur.com/sRfr1.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/sRfr1.png" alt="enter image description here"></a></p>

<p>Can someone guide me in the right direction on how to make this happen? Or suggest a better way to implement it? Also, is there a way to control the size of the entry widgets? I'd like them to be smaller. Thank you in advance!</p>