I added everything back in fairly quickly after the tank is put back together. Put the rock in, then the water. Hook up the powerheads and heater and let it run for a little while before adding the animals ( you should check ammonia levels before adding them just in case).
Tha sand bed, if it is deep 4" or more can cause big problems if disturbed releasing nasties into the water and if it is that deep, chances are it will be way to heavy to carry the tank if the sand is left in there.
You don't have to add any sand back in if you don't want to and the tank may already be bare bottom, saving you a whole bunch of trouble
