switching over livestock

[jordsy]

I am down grading from a 90 gal to a 50 gal. I am setting up the 50 gal first then transfering everything over. What should I do to make sure the 50 gal is ready? should i set it up with sand and just live rock for a few days to cure the water? I heard i should put some raw shrimp in the new water too.... or can i just put the fish in right away?
thanks for your time