Opportunity to learn every facit of every detail of all there is to know about we humans and our blue planet.
If they so desired, they could speak in english (or ancient egyptian for that matter) from moment one...
The advice about preparing for your eventual death at the hands of violent extremists? Probably pretty sound advice for the first person to prove the existance of alien life

PS PS i loved the admonition not to say something dumb when you tell the world about the big moment. Someone at NASA would have done well to have shown a similar chart to Mr Armstrong..