Apparently, the programme has started in the US, UK and South Korea. Samsung also released its first beta Android 7.0 Nougat build in China today and is rolling out the second build for Galaxy Beta Program members in Europe.
The beta will be delivered over-the-air in Europe and those who already have the first beta build installed will automatically receive an update notification. It weighs in at just 92MB and seems to be stability improvements, bug fixes, and performance improvements rather than new features.