Here's how to install Avast Ultimate (Multi-Device)
Includes Premium Security, Cleanup Premium, SecureLine VPN, and AntiTrack as a bundle for up to 10 devices.
2. Once the download is finished, open the avast_premium_security_setup_online.exe file (by default, downloaded files are saved to your Downloads folder).
3. Click Install now and follow the on-screen instructions to complete the installation process.
5. Type the activation code you received with the product into the text box, and click Enter (if asked, enter your name, email, and postal code).
See detailed installation instructions
6. On the My Subscriptions screen, ensure that all products for the recently activated subscription are listed as Active under Subscriptions on this PC. If any products included in this subscription appear under Other available subscriptions, click Activate & install next to the missing product, and wait until the installation is complete.