Basically it behaves like a really big light genoa. A regular spinnaker has both side edges identical, uses a pole to get the sail outboard and is attached only at the top and then has sheets and guys to control the rotation of the sail around the front of the boat and to trim the sail. A symmetrical spinnaker requires constant trimming to maintain shape and is efficient from a beam reach down to a dead run.
A DRS or assymetrical has a short side between the head and what becomes the tack. A sheet to control sail trim is attached to the clew and the tack is attached by a strop or short line to a bow fitting. It trims like a genoa and doesn't need a lot of tweaking to get good results which is why it is popular with cruisers.It is very efficient from a close reach down to just below a beam reach.