How to install Selenium IDE Firefox plugin

Selenium IDE is an integrated development environment for Selenium scripts. It is implemented as a Firefox extension, and allows you to record, edit, and debug tests. Selenium IDE includes the entire Selenium Core, allowing you to easily and quickly record and play back tests in the actual environment that they will run in.
Steps to install Selenium IDE:
1. Launch Firefox and navigate to http://www.seleniumhq.org/download/
2. At "Selenium IDE" click on the link "from addons.mozilla.org"

3.Click on button "Add to Firefox"

 4. Click on button "Install" on popup window

5. Choose "Restart Now" on popup window

6. After Firefox restart, you can open Selenium IDE
Tools --> Selenium IDE
or
Tools --> Web Developer --> Selenium IDE
or use Shortcut keys: Ctrl +Alt +S

Selenium IDE is shown as below