Places any number of objects into a "Tag". The tag can then be referred to in a game script. To create a tag, select the object(s) that will be in the tag (hold Lshift to select multiple objects). Type the name of the tag in the box and click "create". To add objects to an existing tag, select the name of the tag from the list. All objects in that tag should now be selected. Hold shift and select the additional object(s). Click "Apply". Unfortunately, there is no way to remove an Object from a tag (if you have an unwanted object in a tag, you'll need to delete the tag and re-create it)