i would fill the tank with saltwater high enough for you to be able to turn on the powerheads, heater and filter. let the tank run for a day to warm up the saltwater. add a couple of pieces of live rock that will be on the bottom. put in your live sand or dry argonite filling in around live rock. once you have then sand bed depth you are looking for (under 1" or above 5") add the rest of you live rock. since tank is new you can play around with the aquascaping until you have it th way you want it. top off tank with the rest of your pre made saltwater (slowly so you don't cause a sand storm). try to use uncured live rock so that the live rock will cycle your tank as the live rock cures. when cycle is complete you can add your clean up crew and a fish. i personally would wait a couple of months before adding a shrimp or coral so the tank can be a little more established.