Script Download: https://github.com/rg3/youtube-dl
To run it you need to open up command prompt and set the dir to the location of the youtube.dl script. I’m using Windows 10 and have it stored directly on the root of C:
To download the video(s) you simply call the script and the link to the video / playlist. For windows at least be sure to include the quotes around the url! The example below is part of a playlist as you can see in the middle there is &list= which indicates such so all associated videos will be downloaded.
youtube-dl.exe "https://www.youtube.com/watch?v=OSaZc7cKc9Q&list=PLvahqwMqN4M1nAq3XAD_j1qJippzWQcSI"