XPLM_API XPLMInstanceRef XPLMCreateInstance( XPLMObjectRef obj, const char ** datarefs);
XPLMCreateInstance creates a new instance, managed by your plug-in, and returns a handle to the instance. A few important requirements:
The object passed in must be fully loaded and returned from the XPLM before you can create your instance; you cannot pass a null obj ref, nor can you change the ref later.
If you use any custom datarefs in your object, they must be registered before the object is loaded. This is true even if their data will be provided via the instance dataref list.
The instance dataref array must be a valid pointer to a null-terminated array. That is, if you do not want any datarefs, you must pass a pointer to a one-element array containing a null item. You cannot pass null for the array itself.