It's typically an introduction on how the competition flow works and how to be a judge for the competition. While Cyotheking has a good video that covers the competing side of things, it doesn't cover all of what a judge does and is not competition-specific. I'd recommend coming on time to this part of the schedule if it's your first time.
This varies by region. Technically, by the regulations, you need something that proves your country of citizenship, such as a government ID or passport. However, in the US, this is often relaxed, as the typical 14 year old competitor likely has neither of these things. Thus, we typically just assume that everyone is from the US unless they pick a different citizenship, and in that case we verify since they would have to have a passport to be in the US under that circumstance. To contrast, I believe that in Europe they check identification of all new competitors since it's more common for all kids to have a passport.