unwrap etc (expected behaviour)

with the latest release, could someone please check that the uv map selection function etc works. Its something I have never used, but really want to. However, if open a new scene and drop in a cube, select it and then click on UV MAP selection, nothing happens. Now this could just be that I do not understand how to use these functions…..
If I apply a texture and use the UV RE_MAP selection, this works ok.
Is there a simple how to, the help goes so far. But I just can not get the unwrap to work for me.
The way I understand it, is the unwrap selection will make a blank texture of a size you pick and you can edit that in photoshop etc and reapply it to your model……????

pass, I assumed that because the 3 fuctions were side by side they all did the same sort of thing but in different ways, It will nore then likely be the way I am using them, then anything else Dom