I think the best I can do is refer you to some links. The Shumakovs have instructions for bases on their website here:
http://www.oriland.com/oriversity/basefolds/main.asp
Forget what I said about the frog base. I'm going to change my advice a little, but the end result will be the same...
First, fold the "blintz base." This base ends up being a square. Using this square, fold the "balloon base or waterbomb base."
Now refer to this diagram:
http://dev.origami.com/images_pdf/trad_page2.pdf
From the waterbomb base, begin to fold the iris (there are 3 different models on this page, so don't let that confuse you). Continue to fold the iris, but STOP before it tells you to "petal fold." At this point you are basically finished. Just pull and curl the flaps down.