Here is a simple and short step wise guide for installing web player VLC plugin for Mozilla Firefox. Below is the post for How to install the VLC plugin for Firefox.
Step1 : Download VLC version 2.1.3
Step2 : After downloading, run the installation program (if not started automatically) from where you downloaded.
Note : please tick mozilla / firefox plugin and ActiveX plugin :
Step3 : At the end of the installation, quit Setup and any open web browsers to use the plugin to take effect the next time.