Found the site from the sponsors of the project. Bit of a surprise, the Mars, is Mars Candy Bars (M&Ms, Snickers, ect...) Also, a partnership over in Australia on the Great Barrier Reef using the stars. (348 Reef Stars with 5,115 coral fragments of opportunity) Both have fairly extensive pictures of the steel frames coated with sand and the installation.
The main MARRS stats are: "30 sites across ten countries, 60,000 Reef Stars, planting 900,000+ living coral fragments."
Apparently started with "10 years in Sulawesi, Indonesia to restore reefs damaged by dynamite fishing."
[1] https://www.mars.com/news-and-stories/articles/the-big-build...
[2] https://www.gbrbiology.com/2022/04/08/mars-and-coral-rubble-...