Hello,
http://www.d20pfsrd.com/bestiary/monster-listings/constructs/animated-objec t
(There's a space between the C & T in the URL)
Do the rules apply for constructs or only animated constructs, it says animated constructs but I was unsure.
Also, is it possible to stack them?
Generally, only to Animated Objects.
Animated Objects get a "pool" of Construct Points that they can "spend" to add these features. It allows a GM to take a table or a chair, for example, and then give it features that reflect how it could attack.
This way, you don't need 50 to 100 entries in the Bestiary to describe all kinds of variations of objects that could be made into monsters by animating them.
The Bestiary in the Carrion Crown AP added some new ones, and a neat set of new animated objects created with them.
You can "stack" them mostly as long as you have the points in the pool to pay for them.. however, some may require others already be in place (for example, some may require that the "metal" feature be purchased first).