Hello Wayne,
Welcome to Microsoft Community.
Could you please tell me whether you want to activate Windows10 on multiple computers at the same time in your personal capacity, or whether you perform this operation as an organized user?
If you are an individual user, I need to inform you that a Windows10 key or digital license can only activate the system in one device at the same time, not for multiple devices. If you need to use more devices at the same time, you need multiple Windows10 system keys or digital licenses.
If you are an organization user or an administrator of an organization device and need to activate multiple devices in batches, visit the following link and call your local support number as prompted:
Microsoft Volume License Key assisted support telephone numbers
If anything is unclear, please do not hesitate to let me know.
Best regards,
Mitchell - | Microsoft community support expert from MSFT