Both Snowball and Napoleon have interactions with the animals. The strongest example of this can be seen in the third section of the book. Once power has been consolidated in the hands of the pigs, Snowball sets to the task of organizing the farm's activities in the form of committees and groupings that will maximize efficiency on the farm. Snowball also directly interacted with the animals to make sure they understood that what was being done was in line with the revolution's goals and aims. Snowball's interaction with the animals was one predicated upon the revolution and assuming his role as what Marx would have called, "the vanguard of the proletariat." Snowball loved the revolution and his interactions with the animals were based off of this idea.
This was not the case with Napoleon, who "took no interest in Snowball's committees." Instead, he argued that "the education of the young" was the most important and takes nine puppies from Jessie and Bluebell and isolates them along with himself, training them and working with them. They will eventually end up forming the secret police that will insulate Napoleon from the other animals, provide protection for him and enforcement for his policies against opposition and dissent. For Napoleon, his interactions with the animals is predicated upon the notion of power and the distance that comes with it.
Orwell states time and time again that Napoleon "was not one for speeches." This reflects how he interacted with the animals on the basis of power and authority. Snowball loved making speeches and enjoyed interacting with the animals on the basis of the revolution. It is here where a fundamental theme from the work is evident in that it is one thing to declare independence and another to keep it. Snowball's interactions with the animals represents the former and Napoleon's interactions with them represents the latter.
"Animal Farm" is an allegory for the Russian Revolution and the betrayal of the revolution by Stalin and the Communist Party bureaucracy.
Orwell was a revolutionary who supported the idea of a state run in the interests of workers - he fought in the Spanish Civil war. He is sympathetic to the Russian Revolution, but critical of its degradation.
After the Revolution in 1917, Russian society was organised around workers councils (or Soviets). Soviets provided democratic structures in which people debated and implemented the running and organisation of society. The leadership of each soviet was elected by members. After October, the CP dominated the soviets having won support in 1917.
The CP comprised local branches, with a central committee running the party day-to-day. The party congress elected the central committee, and comprised delegates elected by branches.
Congress was the supreme decision-making body of the party; the CC made decisions between congress.
Lenin was the leader, practical and theoretical, of the CP. Two other key figures were Joseph Stalin and Leon Trotsky.
Stalin was a bureaucrat within the CP machinery. During 1917 he was editor of Pravda - the party's newspaper - and subsequently rose to become General Secretary.
Trotsky was a journalist and theoretician, who wrote on Russian, and international, affairs. In 1917 he was elected Chair of the Petrograd soviet, led the October uprising, was elected as the Commissar of Foreign Affairs, and also led the Red Army.
Trotsky argued for the need to export the revolution internationally, and that, without this, Russia would degrade into a bureaucracy.
Stalin opposed Trotsky, arguing to build socialism first in Russia, and only then to export it.
Through the early 1920s, Trotsky challenged Stalin and his supporters through the "left opposition", advocating greater openess and democracy.
Trotsky believed in workers' democracy, while Stalin believed in the supremacy of the party (and its leadership) in decision-making. Stalin, after Lenin's death, made the CC, and not congress, the supreme body, effectively subordinating the party membership to its CC.
Trotsky, by the 1930s, described Russia as a degraded workers state - it was undemocratic but still functioning on the basis of a planned economy.
Here lies the answer to your question. In the book, Snowball is analogous to Trotsky; Napolean to Stalin.
Snowball advocates elected, decision-making committees, but Napolean opposes these.
Snowball encourages the animals to engage with decision making, and to educate themselves. Napolean, by contrast, insists on delegation of responsibility to the pigs, while the animals do the hard labour.
Napolean deceives the animals, operates behind closed doors, and secrelty trains the dogs.
Snowball proposes the windmill to reduce work on the farm. Napolean opposes this, and after chasing Snowball off the farm, claims it to be his idea.
Snowball seeks to win animals over to his ideas through debate; Napolean seeks to force animals to his ideas through deception and the dog-army.
Finally, Napolean's attitude is that of the pigs as a whole (excluding Snowball). Snowball's struggle is against the pigs in general, and not just Napolean. The pigs develop their own set of interests, which separate them from the other animals. So the pigs act increasingly to further their own position, against the interests of the animals as a whole.
This is the essence of the Stalinisation of the CP, and of Russia.