To store the new model type in the library of types go to the interface window and click the right mouse button on the module. In the pop-up menu select item "Export Module Type (xperimental)".
The "Export XML" dialog will suggest to store in the XML file with the name the same as the name of type. If the checkbox "Create interface/fbt file" is checked, then along with the XML file, the header file with *.fbt extension will be saved. Note that headers are needed only for basic models in case if you will use FBDK for editing composite models that include those basic models.