The exporter is a standard 3DS Max exporter that can be found within the 3DS Max export dialog, accessible through the File menu:
Alternatively, you may export the scene through the OgreMax menu:
Once the export dialog has appeared, if necessary, look for the Save as Type labeled OgreMax Scene (*.SCENE), OgreMax Model (*.MODEL), or OgreMax Mesh (*.MESH).
Enter a file name and press the Save button.