Because the Affen is an intelligent little dog that likes nothing more than to please, they are generally easy to train. However, their training and education has to start when they are very young in order to curb some of their more annoying "terrier" traits which includes excessive barking and aggressive behaviour towards people they do not already know.
A puppy’s socialisation has to be start as soon as they are fully vaccinated and this should include introducing them to as many new situations, people, animals and other dogs as possible so they grow up to be more well-rounded and balanced adult dogs.