I believe that three details that support the inference that Napoleon´s actions are motivated bya desire for power and success could be:
- Napoleon makes the windmill more important than everything:
At the beginning of the chapter it is said that after the expulsion of Snowball Napoleon decides to build the windmill, this cause surprise among the animals becuse at first he was against the idea suggested by Snowball, but Squealer convince them that it was a tactic to get rid off Snowball and his nocive influence. From that time on, the construction of the windmill was more important that anything, it was planned to be ready in two years acordding to the pigs blueprints.
Napoleon told the animals that it was going to be a job that requires hard work and it might be necessary to reduce the rations of food in order to get it done. Because they were going to be more focus on the construction than on the crops.
- Napoleon makes changes to trade rules by announcing a new policy:
This way he was the only one to deal with the outside world in spite of going against the rules that they have written when they eject the humans from the farm. The rest of the animals wasn´t sure if they imagined the rules by the intermediation of Squealer who´s job was to maintain the animals paceful and concentrated only in the construction of the windmill. Then the pigs began to break other rules like going to live in the human house, using their beds and waking up one hour later than the rest of the animals. By doing this Napoleon shows that he and the rest of the pigs consider they are more important than the rest of them and break the equity that ruled in the farm since the humans have left.
- Napoleon wrongly accuses Snowball of destroying the windmill
This action shows that he not take responsabilty of his acts and find in Snowball an adversary that could take him the power he held. By accusing Snowball of destroying the windmill turns him into an enemy, not only for him, if not an enemy to the rest of the farm.