Before taking off with How to Download and Install Selenium IDE, there is one thing that needs to be in place prior to the installation; Mozilla Firefox. You can download it from here => Mozilla Firefox download.
How to Download and Install Selenium IDE?
1) Launch Mozilla Firefox Browser.
2) Type URL: https://addons.mozilla.org/en-us/firefox/addon/selenium-ide/ in your browser. Selenium IDE Add-ons page will get open then Click on Add to Firefox button as shown in image bellow.
3) Firefox will show one popup saying do you want to allow Mozilla Firefox to install Selenium IDE Add-ons or not. Click on Install button as Shown in Image below.
4) Firefox will automatically install Selenium IDE software. After the installation is completed, a pop up window appears asking to re-start the Firefox. Click on the “Restart Now” button to reflect the Selenium IDE installation. Click on Restart Now button.
5) On clicking on the Restart Now button, Firefox will restart automatically. In case you missed the pop-up, simply close the Firefox and launch again. Once the Firefox is booted and started again, we can see selenium IDE under the tools menu list. Click on Tools menu list displayed at the top bar. Selenium IDE will be displayed in the list.
6) Click on Selenium IDE, it will launch Selenium IDE.