• Establish connection to your Database.
• Create init_db.sql file in src/main/resources folder.
• Create Manufacturer model.
• Create DAO layer for Manufacturer model. Below you can see the list of required methods.
• You're already given an injector and @Dao annotation. Do not forget to use it for Dao implementations.
• Return Optional when you can return null in DAO. For example: public Optional<Manufacturer> get(Long id);
• In the main method call CRUD methods. It may look like:

public class Main {
    private static final Injector injector = Injector.getInstance("YOUR_PACKAGE");

    public static void main(String[] args) {
        ManufacturerDao manufacturerDao = (ManufacturerDao) injector.getInstance(ManufacturerDao.class);
        Manufacturer manufacturer = new Manufacturer();
        // initialize field values using setters or constructor
        manufacturerDao.create(manufacturer);
        // test other methods from ManufacturerDao
    }
}

WARNING!!! Path to your project must contain only english letters. Also, it mustn't contain spaces. In other case Injector won't work correctly.

• Your table should be named manufacturers and contain these columns: id, name, country, and is_deleted.

• Manufacturer

public class Manufacturer {
    private Long id;
    private String name;
    private String country;
}

- Manufacturer create(Manufacturer manufacturer);
- Optional<Manufacturer> get(Long id);
- List<Manufacturer> getAll();
- Manufacturer update(Manufacturer manufacturer);
- boolean delete(Long id);

e.printStackTrace() - is a bad practice! Let's create custom exception DataProcessingException and constructor with two parameters: String message and Throwable ex.
It should be extended from RuntimeException. You should rethrow this exception in catch block on dao layer.

You can check yourself using this checklist