Hi, I need some help please. Can someone tell me how to make a little square (cube) out of rice bubbles. What do i add to it, any instructions most welcome. Arnt rice bubbles and RKT the same?? Never made it before, so step by step pls. Also once made how long can i keep this cube before it gets spoilt. I will be covering it with fondant.Thanks

Here you go:
(Just use an appropriately sized square pan for the mold.)

http://cakecentral.com/cake-decorating-ftopict-671857-.html

HTH