In this scene, which is the first part of the book, Old Major is making a speech to all the animals about how they need to rebel against Mr. Jones and make all animals equal.
In this scene, after Old Major dies, the animals are finally rebelling against Mr. Jones and chasing him and his workers off the farm. This is when the animals take over.
This scene is when the pigs come up with fair laws called the Seven Commandments. The animals use the Seven Commandments as a guide for what they are supposed to do and who they are supposed to interact with.
This is the Battle of the Cowshed when Mr. Jones tries to take back the farm and surprise the animals with an attack. Luckily, the animals use their strength to defeat Mr. Jones once and for all.
This is when the animals finally finish the windmill and they realize that they are better off without Mr. Jones and they can do stuff for themselves.
This is when the pigs start walking on there hind legs and they start looking like people.