Best way to swap everything over to new tank?

[Gripenfelter]

So I need to swap coral, fish, lights, and refugium from my 120 gallon to my 300 gallon. The 300 gallon is dry right now.

I have cured cycled rock with mushrooms and zoas growing on the rocks already too. The 300 gallon doesn't have a sump yet.

So what would be the best way to switch everything over? Like do I do it in stages over a few days or everything all at once?

I was thinking of putting in the rock, some new sand, then the old rock and corals, then the fish over a few days.

It will take me a full day to mount the lights from the 120 gallon on to the 300 gallon. LEDs.