It all depends how strong your lights are as well, generally soft corals will need a much lower lighting level so they can be placed on the bottom of the tank. SPS need a really high level of light so they go toward the top and LPS can live from the bottom to the top depending on how strong your lights are.
If you have information on what lights you have we can tell you places to put your corals.
You can also tell whether a coral is doing well or not and then change their position. Light plays a major factor in creating healthy corals.