Click on the "Add to Firefox" button
You will find this button on the mozilla add-ons for firefox page. 
Firefox security warning
It is possible that Firefox block the installation. You will see a yellow bar in the top of the page, telling you that the installation is blocked. You must click on the "Allow" button, at the right of that yellow bar, as you can see in the image below.
Add-on setup
Click on the "Install now" button to start the setup.
Setup completed
The setup of the video downloader is completed, click on the "Restart Firefox" button.
The video downloader is now ready to be used !
You can now use the Ant video downloader, it's very easy :1- Play the video you want to download, from any tube site.
2- Click on the "Download" button, located in the bottom right of your Firefox browser.
