So to make a flower using those petals, you'll need gum glue, a circle of wafer paper, and the petals.
First, make sure that you're working on a surface that won't stick to the gum glue, like something plastic or a silicone mat. Paint a bunch of gum glue on the circle. You want the whole thing to be covered but not too goopy.
Now take some of the larger petals and put them on the glued-up circle. You might have to press them into place for a minute to make sure they stick. The petals will soften where they touch the glue, and that's okay. In this photo you can see the circle showing through the petals, so that's about how wide it should be to make sure it attaches securely.
You can then start adding petals to the center of the flower. I painted the gum glue directly onto the petal for this part, then pressed them into the center of the flower, holding them in place until they soften a little from the moisture of the glue. When they soften they'll adhere to the first row of petals.
Do another row of petals if you'd like. You can add as many as you want to make the flower as closed or open as you want it to be.
Once you get the number of petals that you want, add a center if you want the flower to look more open. I made this center from more wafer paper, but you can make them from gumpaste or artificial stamens if you prefer.
Now it's time to let the flower dry, so leave it alone. Let it dry COMPLETELY. It will be very secure when it dries if you used enough gum glue, but it can fall apart if you try to move it around too soon.
I dusted the center with some yellow petal dust for the final flower. You can also go back and add some more petals onto the back of the flower at this point if you want it to be even fuller.
To attach this flower to a cake all you need to do is insert a toothpick or a wooden skewer into the back of the flower, then into the cake. You can also dip the toothpick into the gum glue before inserting it into the flower if you want it to be permanently attached.
Next up will be another method of wiring the petals, so watch for that on Saturday