It is there, first find the main tutorial for "Folded Dahlia", instead of cutting squares for the petals, cut strips 6 x 3 1/2 inches, fold over 1/2 an inch on the long side wrong side to wrong side (this gives a neater finish) and then press the 3 inch side to the 3 inch side (right sides together) to give you your centre fold.
Follow the main tutorial for assembly, I would advise to do a few tacking stitches at the bottom of each "Petal" to hold it firm and I always do a row of top stitching around the last "Petal" to stand up to laundering.