Here is a step by step guide on how to make gum paste/fondant flowers for cake decorating. I learned how to do this a couple of months ago, and I was intimidated before I went, but it is quite simple and so I wanted to share.
Remember as you go to reapply Crisco to whatever needs it. This mixture (gumpaste/fondant) is very sticky and delicate, and the Crisco helps it not to stick or tear. Grease your small fondant rolling pin and roll out the gumpaste/fondant as thin as you can, also as evenly as you can. You should be able to see the lines of your mat clearly when it is thin enough.
Using your fondant cutter, cut out as many flowers as you can. Make sure you press down firmly, so that the cutter cuts all the way through.
Carefully transfer your flowers to a space where you can keep them covered as you work, so they don't dry out. (The Wilton practice board is perfect for this job.)
Dust your fondant pad (with your dusting bag-filled with 1 Tbls cornstarch and 1 Tbls powdered sugar). Get out your veining tool and working with one flower at a time,
Ahead of time, make your gum glue. 1/4 tsp gumpaste dissolved in 1 Tbls or so of water. Break the gumpaste into little pieces and let it dissolve.
When you are finished with the petals, and have completed 2 flowers, dab the middle of one flower with gum glue
And press another completed flower on top, alternating the petals, in between one another, so it looks like this.
Dab some gum glue on the center of your flower and put the ball on top. Press down the ball to flatten, and carefully transfer to a small flower former.
Continue with other cut-out flowers until you have enough for whatever you are making. Remember also to keep all gumpaste and fondant that you are not working with cover tightly, so it does not dry out.
When you are finished making all your flowers, place the flower formers on a cookie sheet and place the cookie sheet in a cool, very dry place where the flowers can dry for 2-3 days before you need to use them.