1 description Go to www.Firefox.com and download the free web browser and if you don't already own it  2 description Wait until Firefox is installed, then open and look at your tool bar,click on the one that says tools,click on the tab that says "Add-ons" 3 description Open a new window,on the lower right hand side of the new window there is a link that says "Get Extensions",click it 4 description Be at the Firefox websites add-on section,click on the search box and type in "grease monkey",download grease monkey and install 5 description Install grease monkey follow this link Install and click install this script on the right hand side,install the script 6 description Make sure grease monkey is turned on so go to tools,click add-ons and click enable on grease monkey ,if it isn't already 7 description Click on the grease monkey option's new window will open and on the lower left-hand side click the box that says enable 8 description Source: http://www.wikihow.com/Download-Facebook-Videos-Free