You can customize parts of ApiOmat with modules. Modules can be:
Connectors to internal legacy systems or other 3rd party systems
Provide a way to implement business logic
Provide a customized RESTful interface
Provide a custom authorization machanism
Additionally, to improve deployment with your load balancers, you can implement a notifier.
In this section it will be supposed that Eclipse is used as a development environment.
In most cases, it is necessary to create a new module first. If required, other modules can be "used" / imported once this is done but the major part of developing a module is expected to consist of working with the native module technology.
You will most likely need to access objects of meta models in your module. Please note that there also is a sub-chapter for Accessing Data which is meant to provide an overview of available methods.