First I pinned the darts on the dress form, then I marked the darts with basting stitches.
Next step was cutting away the excess fabric. This was a little nerve wrecking. Luckily I had some more lace if this didn't work out.
With small stitches I closed the dart (this is the sample).
Now I will have to do the same on the back pieces, but hopefully it will be easier since they are much flatter. I rather not make any more cut-out darts in the lace!