Sign in to the account of Microsoft Office
Once you've accessed the office.com/setup website, you now need to sign in to your Microsoft Office Account, or if you don't have one, you can easily create a new account.
Enter office.com/setup Product Key
Now that you've signed in to Microsoft Account, you'll need to enter your 25 Digit Alphanumeric Product Key with your Microsoft Office Password. From drop-down menus, pick your country and language as well.
Download the file to install
When you enter your product key and other information, it will verify your product key and lead you to the next site. You'll see your brand and your subscriptions here. Just next to your subscription details, you can press the Install button. You should start downloading your brand setup.
Run the office.com/setup Installation File
Your file is downloaded, now you just have to press and run the script. You can run it manually from the directory of your downloads. You should receive a request from your operating system, press Agree and then click Agree. Start your installation.
Run Office Apps and wait until the installation process is complete. When complete, the installation window will show "You're All Set." Now press to complete and open any Office App. You will receive a walkthrough the window and you will receive a message that your Office is activated and allowed.