What changes did Napoleon make first in chapters 4–6 of Animal Farm?

In chapters 4–6 of George Orwell's Animal Farm, we see the implementation of Napoleon as leader of the animals. Snowball has been expelled by Napoleon's dogs, so now there is no resistance to Napoleon's leadership. The very first change Napoleon makes is to get rid of the Sunday morning meetings. The decisions that were discussed at these Sunday meetings will instead be made by a council of pigs, presided over by himself. The animals are upset by the change, and several of them try to articulate their thoughts in order to speak out against it; the young pigs who are bold enough to do so are immediately silenced by Napoleon's dogs, and the issue is abandoned.
The second change is Napoleon formally putting himself in charge of the farm. It is explained as a heavy burden, a sacrifice that Napoleon is making, and again, none of the animals have the words to argue against it. With the option for debate removed from Sunday meetings, Napoleon commands the animals to gather for their orders for the week on this day. No one is able to protest the arrangement, and work on the farm continues.
The third biggest change Napoleon implements in chapters 4–6 is the pigs' residence in the farmhouse. Some of the animals question this move, as they believe they faintly remember a resolution against living in the farmhouse in the early days of their revolution, but as none of the animals are able to prove this, and as the resolution had not been written down, the animals are convinced by Squealer, one of the pigs on Napoleon's council, that this is a perfectly acceptable move.