It's pretty straightforward; basically, it's a plant. It does photosynthesis, so it needs light, carbon (in this case alkalinity), macronutrients (Nitrate, Potassium, and Phosphorous), and micronutrients.
If you have a very low nutrient reef tank, it may grow slower than it would in a more nutrient rich tank, but it should grow comfortably assuming you're feeding your fish well. If it gets extremely large, it's possible that it could get nutrient limited by one of the three macronutrients or possibly a micronutrient (Iron is a common one to look at in marine plants). In that case, fertilizing might be a good idea for the algae, but most reef keepers get nervous at the idea of adding nitrate or phosphate into their reef. I think you're a long way away from that, so don't worry to much about it.
Also, herbivorous fish and invertebrates might eat it, so weigh those options before adding herbivorous blennies or crabs/snails.
Honestly, in my experience most red algae is pretty durable in a reef once it survives the move. Just put it in a spot where it can't spread too quickly throughout the rock work, and continue to test your water for nitrate and phosphate like you should. It should stay viable for a long time. Good luck with it- it's a cool find.
