Help with upgrading a 29 gallon saltwater to a 75 gallon tank?

Place the new tank in stand all in place. Rinse your new sand and cure the rock. Fill the new tank with saltwater and wait for it to cycle. Do water changes weekly. Add your bigger skimmer, filtration, thermometer, and powerheads. Add fish slowly and if you keep those 2 fish in the old tank, you should keep the rock and sand in there, but if you ever decide to move the fish to the bigger tank, then I would recommend to use the old tank for a medication tank which you can keep your newly bought fish or sick fish in until they are healthy for your bigger tank.