This was so much fun to make and so very easy!  I hadn't done any tie-dying since I was a teenager and the process back then always involved buckets filled with Rit dyes.  It was quite difficult to do multi colors and it was extremely messy.  Leave it to I Love to Create to come up with a kit that included everything you needed to tie-dye.  The only thing I had to supply was the onesies.  Here's how I did it.
First, you need a Tulip Tie-Dye Kit.  There a lots of choices and I went with the Neon. You will also need a button (not the three you see above), a flower cookie cutter or flower shape of your choice, scissors and thread.  For this project you need two onesies.
The instructions enclosed in the kit are excellent and I had no trouble following them.  For the main onesie, I went with the swirl method and this is what the onesie looked like after I put the rubber bands on.  Remember to prewash your item before you tie-dye to get the best results.
Lay down some plastic to protect the surface you are working on.  The tie-dye kit has premeasured dye in bottles and all you need to do is add water.  I chose to use the pink, orange and yellow.  Next I squirted sections across from each other in the same color.  Turn over and repeat. I let it set for 7 to 8 hours to allow the colors to set.

                                         I squirted dye all over.  I used only one color.

I pressed the flower cookie cutter into the fabric and it left a nice indentation.  Cut out.  You can also find a flower shape, trace it onto the onesie and cut out. 
 Center the flower on the onesie, place the button on the center of the flower and stitch in place.