First, pull apart your silk flower, so that you can use the petals.
Next, cut out your scrap of fabric into the shape of a circle.
Then place your magnet on the fabric and glue a ring around it.
Place the bottom silk petals on the scrap fabric, so that they cover the ring of glue. (Also, if you stop to take a picture your glue will be too dry and you have to rip it off and do it again.)
Finish hot gluing the flower petals onto the first ones.
Add a button to the center of your flower with hot glue.
If wanted, add leaves to the back of your flower, but try not to cover the magnet. (Also, you could add them before the petals)