How to add functions to python App - YT video dowloader?

I’m trying to develop some projects for python beginners,
so I found this App for YouTube downloader source code,
I need to add some other fucntions:

  1. how to select the field where to save the file (video)? = (code)
  2. how to select the quality of the video, high resolution, sound only, low resolution = (code)
  3. how to export this app as exe file to be on the desktop?
    See the app source code in below, please help to add the above mentioned functions,
    import tkinter as tk
    from pytube import YouTube

#Dispaly Window
dock = tk.Tk()
dock.title(“Youtube Video Downloader”)
tk.Label(dock, text =“Youtube Video Downloader”, font =“arial 20 bold”).pack()

#Enter the URL
link = tk.StringVar()
tk.Label(dock, text =“Paste Link Here:”, font =“arial 15 bold”).place(x=160, y=60)
link_error = tk.Entry(dock, width =70, textvariable = link).place(x =32, y=90)

#Function to download the video
def Downloader():
url =YouTube(str(link.get()))
video =url.streams.first()
tk.Label(dock, text =“Successfully Downloaded”, font =“arial 15”).place(x =180, y =200)

#Download Button
tk.Button(dock, text =“DOWNLOAD”, font =“Verdana 15 bold”, bg =“orange”, padx =2, command =Downloader).place(x=180, y=150)