In the createObject, you should return the object which will be consumed and published by the data source. Note that, once returned this way, it is "owned" by the data source, and you should not store it in a different place (ex: managed bean...). The object also have to be Serializable.
saveObject means that the user trigerred a save action (ex: submit button) and the data hold by your object should be saved to your back end database. The action to take here tighly depends on your object implementation