A region is an area on the map that corresponds to a place in the real world where you want a sound to play or an image to display on the screen. You can create the regions in the size and shape that you want. Regions can be used to 'trigger' sounds and images to play/show when someone walks through a region on your map. You can attach events to them so that things happen when you enter and exit the region in the real world.
Tip: When you create a new circle region, it has a radius of around 64 metres. When you create a new polygon region it is around 64 metres square in size.