This is a 65g, just rock, sand, Aquaclear HOB filter, Coralife HOB skimmer, 2 Jebao wavemaker, two Visparspectra 165watt lights, an optical ATO.
While there’s always an advantage to have been in fresh, that’s not a requirement at all.
First step is to get your tank, rockwork and sand in.
Carib-sea makes a good sand
Make and use RODI water, the salt of your choice, and mix a Batch to 1.026, repeat until tank full
Add a full bottle of bacteria.
Add heater.
Add filter.
Start wavemakers.
Leave lights off.
In one week, add your first or two, start with least aggressive first or a clown pair.
Let that settle.
Repeat slowly until you have a few fish in your tank.
You can add some light, just remember light brings algae.
keep a very close watch on your nitrate and phosphate during the first 9 months, gotta keep them in the ranges. Nitrates running in the 5-15ppm and phosphate in the 0.05-.1ppm range is good for a mixed setup.
when you can stabilize both those and salinity, try a couple of softies.
When we move to Stoney corals, we need to maintain ALK, CA and MG, in addition to salinity, temp, nitrate, phosphate.
When you can maintain all those stable, feel free to add all the corals you want, just be mindful of the space, each requires to grow out.
Great luck and have fun.