Problem with associations and nodes

Hi,

I have been defining a model with objects and attributes, something like an Entity Relationship Diagram (ERD). I have different objects for instance: BO_Event, BO_Type, BO_Contact, and so on. These objects have their corresponding alternative keys, attributes and associations. But I don't know how do I have to create these Objects, because the objects have associations 0..n, 1..n, n..m and I don't know how can I define relationships in a correctly way using associations and nodes.

Thanks