To second Joe, I wouldn't recommend you use tap water unless you have it tested for disolved solids such as heavy metals, chloramine, chlorine, copper,phosphates etc.....rather than go to that much trouble just go to a water distriibutor and buy a bunch of 5 gallon jugs for your initial fill. Fill up the tank and mix in the salt mix to an sg of about 1.025. Let this mix overnight and heat it to your temp you want. Then add your live rock placing it on the bottom or some people place it on eggcrate (light diffuser with the small squares, you can buy a sheet at Lowes or Home Depot for about $10) Once you have your aquascape set up then add your sand and the best way to do this is to lower the bag into the water and slowly slide the now wet sand out of the bag with as little disturbance as possible to reduce the sandstorm that is inevitable. Let this all settle for 24-48hours then start up the powerheads for movement......The rock should jump start your cycle and you should then start testing......try not to get the sand on the rock if you can, if you do, get a turkey baster to blow it off afterwards and once the dust settles you will want to squirt them off as the dust will settle on everything in the tank......the bacteria off the rock will help it settle out.
As for aquascape look at pictures of peoples tanks to gain a unique set up. Remember to leave enough room between the rock and the glass to accomodate a magnet cleaner.....and room for water movement around the rock. Fish like caves and tunnels and places to hide. Good luck and we are awaiting pictures.