The are two ways how you can download video from youtube.
1. Using Youtube Downloader
This is kind of software that works for Mac and PC. So you can use it. And it is totally easy.
This software is for Mac. It is a little bit different from for PC. But the way how you do it is just the same.
Step 1 : Copy your video URL from the Youtube. It starts with www.youtube.com/xxxxxx
Step 2 : Paste it in the Youtube Downloader. Wait for it to analyse.
Step 3 : Press "download". And it will be ready for you.
Step 4 : Check out where is the video being downloaded. And the it is .