What events lead to the beginning of the rebellion In animal farm?

My reaction to snowball's expulsion from Animal Farm was very surprised. At this point in the book the readers would expect Snowball to be very respected for his wonderful ideas (especially the windmill). Instead, Napoleons twist also twisted my mind at first. Throughout the rest of the book, however, I realized this pig's plot and realized how great snowball really was :(

hope this helped!