Anyone could explain ep 12 i couldnt able to understand whats happening?

daxs4 said:
@Mugiwarayaa___ The keys that the Tendoushuu have are the keys to control the Altana of a planet at will and since Utsuro is an Altana being (Altana mutant), the Earth's Altana would give him more power/strength, so he tried and succeeded at obtaining the keys. He also destroyed other planets with some of the keys, in order for other aliens to start rebelling and eventually start a war against the Tendoushuu, whose base of operations is the Earth (Utsuro's ultimate goal is to die and destroy the Earth too, which he plans to achieve with the power of the key and by having other alien armies attack the Earth).

The second part of the question, when you say "these people" I assume you're perhaps talking about the Tendoushuu?
The Amanto are just random aliens who came to live on Earth or visit it, it's just a name for all the aliens in Gintama in general and the Tendoushuu are the organization that controls the Earth and the large portion of the Gintama universe; so no real connection there.