After cutting eveything out, just install the clockwork on the back and assemble the hands on the front. Now you can place the butterflies as you like them to be flying. You can glue something on the back to make them the same level as the clock

For the numbers I used clear UV-resin to attach the loose parts of the numbers. If you don't want to do that, just use the second version where you don't have loose parts on the numbers.

I moved the butterfly in the clock a little bit, so you don't see the clockwork through it as in the picture