This is the “true” Eden way of adding emitters, via an entity's attributes.
Not all entity types are supported (those on which it would not make sense to have these attributes).
Map objects are also not supported. It is not possible to edit the parameters of these emitters from within the attributes, but it is possible to edit them via the Emitter 3Ditor after setting them up.

So, let’s pick for example the BMP2 Wreck (Props → Wrecks → APC) and open it’s attributes.
Expand the section Emitter 3Ditor, tick the Use object as emitter box and the following should activate:

enable/disable the emitter attributes/emitters for the entity. If this has been activated before and the entity already has emitters set up disabling this and pressing OK will delete the emitters.

The amount of emitters to insert, 1 to 5

It is possible to have the emitter(s) appear on selected object model selection (selected from the Model selection list), this links the selection selections between emitters so that if you change one emitter’s model selection all emitters will get the same change.

Same as above but for the die out timer

Checking this box makes the emitters “follow” the entity’s hideObject state in scenario in-game. When the entity is hidden with hideObject the emitters stop emitting, and when the object is set visible again with hideObject false they start emitting again.