How do Napoleon and the pigs achieve power in the novel Animal Farm by George Orwell?

Napoleon and the pigs achieve power through their leadership of the revolution that overthrows Jones, the human owner of Manor Farm (renamed Animal Farm under the pigs' leadership). The pigs are the smartest of the animals, and it becomes clear fairly early in the aftermath of the uprising that they will occupy positions of power and privilege on Animal Farm. For example, the pigs claim they need apples in their mash, a privilege not extended...

Napoleon and the pigs achieve power through their leadership of the revolution that overthrows Jones, the human owner of Manor Farm (renamed Animal Farm under the pigs' leadership). The pigs are the smartest of the animals, and it becomes clear fairly early in the aftermath of the uprising that they will occupy positions of power and privilege on Animal Farm. For example, the pigs claim they need apples in their mash, a privilege not extended to other animals, because their minds are so essential to the organization of Animal Farm. Over time, Napoleon, with Squealer as his obsequious propagandist, purges his rival Snowball and begins to solidify his power with a combination of brutality and deception. They claim that Snowball is constantly conspiring to destroy the farm and that Napoleon, not Snowball, was the architect of the windmill. Using the dogs, Napoleon has dozens of the animals killed in front of the rest for allegedly committing treason. By the end of the book, the pigs are walking upright, wearing clothing, drinking and playing cards, and are indistinguishable from their old human masters. This process is most clearly demonstrated by their manipulation of the Seven Commandments written on the barn. At the beginning, they contained seven rules intended to establish equality among all animals. By the end of the book, there is only one commandment that assures the rest of the animals that while all animals are equal, some are "more equal than others."