Now, you can start creating your classes in template structure;

1. Create the controller class. Ex: ProductForm, ProductList;
2. Login as administrator (admin), in order to register the permissions;
3. Register the class as a program (Administration -> Programs). You must fill the "controller" field with the class name (Ex: ProductForm);
4. Give permission on the registered class to some user or group (Administration -> Users or Administration -> Groups);
5. Add the program to the menu.xml, that contains the menu structure;
6. Perform a logout and login with some user with permission to run the created program;
7. Finish the program creation.