To install AdBlock, access the Chrome Web Store or the Add-ons section on Mozilla.org, depending on your Web browser, find the AdBlock extension using the search functionality, and download it. Once the necessary files are downloaded, your Web browser should automatically complete the installation process. To modify the settings of the AdBlock extension, access the Extensions section within your browser. As of 2015, the AdBlock extension is not available for Firefox, but Adblock Plus serves as an alternative.
In Google Chrome, click on the Menu button, hover over More Tools with your mouse pointer, and click Extensions. Navigate to the bottom of the page, and click on the Get More Extensions link to open the Chrome Web Store. Type “AdBlock” in the search field, click on AdBlock in the list of results, and then click on the Add to Chrome button next to the AdBlock entry in the Extensions section. Once the automatic installation completes, the AdBlock icon should appear next to the address bar.
In Firefox, click on the Menu button, and select the Add-ons option to open the Add-ons manager tab. Click on Get Add-ons, use the search field to find Adblock Plus, click on it, and then click on the Add to Firefox button. Confirm the initiation of the installation process once the extension is downloaded, and select Restart Now once the installation completes.