Using this software is very easy, just run the 'main.py' file. You will get a Tkinter window. Enter your message in the message entry and a key in the Key entry and click on Encrypt button. Now the you can copy and send the encrypted message which you will get in the output section. Remember the key which you have chosen to encrypt the message plays a very crucial part in the decryption of that message. Mistake of single character or even a single space will lead to wrong decryption.
Demo of the program: https://www.youtube.com/watch?v=wFZdYKLUT1o
Understand the Algorithm: https://www.youtube.com/watch?v=DLjzI5dX8jc