First, you'll have to enable the appropriate plugins from the "Open Graph" plugins group. For instance, if you want to create an object for Joomla articles, you'd enable the 'Open Graph - content' plugin. Once enabled, you should be able to choose from those in the object list when trying to create a new object.
If you need further details on how to create objects, please check out
our guide
.
Please let us know if you continue to have problems after trying the above.
-Melissa