Enabling extension

[Invisible40]

How do I enable the extension to Chrome? Sorry for the stupid question.

[svtux]

What is the main problem?

If you can't install user script then you need use one of the many articles from web "how to install userscript to google chrome", e.g.:
http://stackoverflow.com/questions/5258989/manually-adding-a-userscript-to-google-chrome
http://techsupportguides.com/install-userscripts-in-chrome/

1. Download the script - youtube-video-download.user.js
2. Click on the "Customize and control" icon and go to Tools > Extensions
3. Drag the script onto the page.

NOTE: Chrome will warn you that the script can "access data on all websites". That is Chrome's generic warning for any user script. Read the code of the of the script to determine what it does.

If you can't use current script - this is a bug which has been fixed in my fork. You can find it here:
https://github.com/svtux/youtube-video-download