It is in Chapter Five of Animal Farm that the subject of building a windmill first emerges. For Snowball, the windmill is an exciting prospect because it can be used to build a "dynamo" which can supply the farm with electricity. Once the farm has electricity, Snowball plans on building a range of "fantastical machines" which will improve the lives of the animals by giving them lighting, heating, and labor-saving devices.
In contrast, Napoleon really disapproves of the windmill. In fact, at one point, he urinates all over Snowball's plans as a means of expressing his discontent. In addition, Napoleon argues that the animals should focus on increasing food production instead of building the windmill. In his mind, the windmill represents a waste of time and energy.
Ultimately, Snowball wins over the animals, but Napoleon will not let Snowball be victorious: he runs him off the farm, never to be seen again.
Snowball wants incubators and heaters and a 3-day work week, whereas Napoleon wanted a longer work week to store up the food.
Although Snowball's idea would provide luxuries and comforts, Napoleon's idea is logical and considers the needs of all the animals for the here and now. That will change, in fact as things move along, Napoleon takes credit for the windmill but doesn't have the ideas Snowball had to put it to work.
Considering how Snowball(Trotsky) and Napoleon(Stalin) acted might help you draw conclusions about the differing leadership traits of their Russian Revolution counterparts.
At first, (this is in Chapter 5) Snowball wants to build the windmill and Napoleon does not. Snowball thinks that having a windmill will improve the lives of the animals. He thinks that they will be better off if they have the windmill to make electricity for them. He thinks it will make them more comfortable. Napoleon thinks that they should concentrate on just growing food instead of worrying about comfort.
Napoleon wins this argument, but not by having better thoughts. Instead, he just gets his nine dogs to chase Snowball off the farm.