Want to change from farmer to a raider how to do it?

Class changes are now done via the Class Hall Building. There are now 4 classes to choose, each has 2 options but only 1 is available at the moment. If you aren't at a level where you can change class for free you need to buy a class change item. When you go to the class hall and select 'class' you should see at the bottom if you have a class change available or what the next base level is that you need to reach.