Click on this link- https://www.avast.com/en-in/secure-browser and it will take you to the Avast official website.  Click on the ‘Free download’ button. It will download the file in your browser’s download section. Run the app file, follow instructions and it will get installed on your computer.  Once installed, you’ll see a shortcut has been created on your desktop. Double-clicking on it will open the browser for you.