Cody's lab had a nice 5 video series on making it at home! But the United States Government asked him to take it down as suggested at Video 160. "What's Been Going On With Cody'sLab? by Cody's lab (2019)" at https://youtu.be/x1mv0vwb08Y?t=84.
Here's a copy online as of 2020: https://www.youtube.com/watch?v=bCXB6BdMh9Y