ObjectTemplate.AddTemplate

MDT description

This command property is used to attach a child object to another object. Any SetPosition and SetRotation commands following this will apply to the attached object, until another AddTemplate command is encountered.

The first argument is the unique name of the object, set by a Create command.

For an example, see the HasStartEffect property, which shows a muzzle-flash effect attached to the barrel of a defgun.
Source and more details