Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Which Microsoft product is this? If you have a subscription, the process should be straightforward. Start your new computer and install from your associated account at https://account.microsoft.com/services . You activate the product by signing in.
One-time payment licenses may run into issues with activation after you install them (because each one-time payment license is for a single user and a single device). If that happens, see https://support.microsoft.com/en-us/windows/activation/activate-microsoft-perpetual-products-using-the-product-activation-portal .