Do I need to change the "environment" in material editor?

I have recently downloaded “dream big characters” from the lumberyard website and i am going through the material editor to apply skins and what not, is there a point in changing the “Environment” from “nearest_cubemap” to something else and if so what do i need to change it to? As well I am unsure what the cube image is about in the picture if anyone would care to tell me what that is about.

@Skeptic

The cubemap provides lighting and reflections in your levels. For the most accurate representation of your level, you will almost always leave this at ‘nearest_cubemap.’ Sometimes you might want your materials to reflect a specific probe so you also have the option to choose which probe to reflect.