Step 1 : When you click on Classes Sub-module under Academic Settings Module below window will show on your screen. Here you can manage Classes.
Step 2 : On the top right hand corner, Add New Class button is available which can be used for adding new class.
Step 3 : And when you click on Add New Class below window will popup on your screen. Here you can add new class.
Step 4 : In the below fig in Red circle you chose Class Group & from blue circle you can assign class to Teacher.
Step 5 : After Saving, the new Class list will show here you can Assign Class Teacher & Modify Class. All action button will show in below Figure.
Step 6 : When you click on Assign Class Teacher link a popup window will appear on your screen, here you can reassign Class Teacher.