Coral restoration typically involves growing coral fragments in a nursery, often suspended on underwater frames, before transplanting the grown pieces onto a damaged reef, a slow process that can take years to produce a meaningful, visible difference to the health of a struggling reef ecosystem.
Patience is central to the whole approach, since coral grows slowly under the best conditions and even more slowly under the stressed conditions many reefs now face, which means restoration projects are usually measured in years and decades rather than the shorter timeframes most conservation efforts operate within.
Success depends on more than simply planting new coral, since the underlying conditions that damaged the reef in the first place, water quality, temperature, local pressures, generally need to be addressed as well, or the newly transplanted coral will likely face the very same threats that harmed the original reef. None of this is especially glamorous, which may be exactly why it works as well as it does.