Summarize the following:
It's the button with the Windows logo in the lower-left corner of the taskbar. Click a product such as Word or Excel to launch the program. If you don't have Microsoft Office installed on your computer, you can  download it online. It's below the icon with an image of a key. It's the in the "Activate" option. Type the email address and password associated with your Microsoft account. This will complete the activation.

Summary:
Open Start . Click an Office product. Click Activate. Click Sign In. Sign in with your Microsoft account. Follow the prompts and click Next.