For the flowers, I cut the felt sheets into strips.
Then, I used embroidery thread to sew them together into loops. Be sure to leave plenty of extra thread for hanging these different lengths on the mobile.
Cut out leaves from the green felt, pinch the ends, and sew two together. You can use these to tie around the hoop or have hanging inside the mobile.
Cover the hoop with the bias tape. Add embroidery thread to the center, in a criss-cross pattern. Then hang the flowers and any hanging leaves on the mobile. I found it was easier to work on this with the mobile hanging, that way I could see how much the pieces hung down and covered each other. I just added one nail to a doorway so I could hang this at a comfortable height to work on (a command strip hook would also work).
Once you have all the pieces as you like, trim off any excess embroidery thread.