Hi Mike,
Welcome to the Microsoft Community. Thank you for your support of Microsoft products!
Please note that the LTSC is intended for organizations and is not generally available for direct purchase by individuals. The following two options are currently available for individual users. (Click to jump to the official purchase link)
You can also refer to this document below for a quick overview of the new features and functionality of Office 2024.
What's new in Office 2024 and Office LTSC 2024 - Microsoft Support
If you have already purchased a key from the official platform or a third-party store, log in to the following website and enter your key to activate it. If you decide to buy from a third-party platform, choose a recognized and reliable platform such as Amazon.
Setup Office - Office 365 Redemption
To install Office, visit Microsoft Account on the PC or Mac that you want to install Office on. Sign in with the Microsoft account that you used to purchase, or have already associated, with the subscription or one-time purchase product, and then follow the onscreen instructions to install Office. Learn more about how to install Office.
I hope this is useful and please feel free to ask any questions.
May you have a good day!
Best regards,
Ian - MSFT | Microsoft Community Support Specialist