I used a blue washable marker to mark the grommet placement, according to the pattern markings. The kit has two small tools to help keep the two grommet pieces lined up so they can be hammered together. When hammering, a few firm blows does the trick. Beyond that, the grommet can get flattened and have some sharp snags in the opening.
Altogether I used 24 grommets, six on each side front and back. A bit time consuming but easy to do. I'm sure I'll use this technique in the future with art quilts; lots of possibilities! The 1/8" yellow cord laced through the grommets completes this part of the gown.