from various sources
https://www.youtube.com/watch?v=oBt53YbR9Kk&t=14169s&ab_channel=freeCodeCamp.org
https://www.youtube.com/watch?v=f2xi3c1S95M&ab_channel=KeepOnCoding
https://www.youtube.com/playlist?list=PLrmLmBdmIlpsHaNTPP_jHHDx_os9ItYXr
and more...