There are several types of planes that make up the universe. The types are planes of existence, elemental planes, planar bubbles, and graveyards. An example of a plane of existence would be Tyrra itself. An example of an elemental plane would be the plane of life. An example of a planar bubble would be Essencia. An example of a graveyard would the Graveyard of the Four Winds. Every plane, regardless of what type of plane it is, exists independently of all other planes, with its own timeline and its own substance.
There are twelve types of elements (perhaps thirteen or fourteen depending upon how one counts time and void). The first four are the physical elements. These are fire, water, earth (stone), air. The other eight are known as the immaterial elements. These can be broken down into the metaphysical and spiritual elements. The metaphysical elements are light, dark, order, and chaos. The spiritual elements are life, death, dream, and reason. Each of these elements exists in opposition to one other element. For instance, order opposes chaos, and water opposes fire.
Certain forces, such as destruction, seem to be elements, but in fact are combinations of other elements. Any plane said to be representing one of these sub-forces is actually a planar bubble. These planar bubbles tend to exist in between other planes. For instance, destruction might exist between death and chaos. Of course, it is interesting to speculate how a plane based around destruction could exist without being destroyed by its citizens, but that is a question for another day.