OK you will need a heater, couple of powerheads with a combined turnver or greater than 550 gallons per hour. Aragonite sand (live or standard) salt and RO water/unit. Tests kits (PH, Ammonia, Nitrite, Nitrate and Phosphates) and a Hydrometer
Fill the tank 2/3 with pure RO water and heat it to the correct temperature and then add the salt. Get the SG between 1.021 and 1.026.
Add the powerheads, usually in teh rear corners facing the front center of the tank to create turbulance.
Now add the sand... If its live sand then drop the bag in and open it allowing the sand to pour out. If its not live then clean it and put in the tank (the tank will go cloudy but this is expected). Use aragonite sand if possible as this helps buffer the water and is rich in calcium.
Make sure the sand is no deeper than 2 inches and to start wi th i would advise a depth of no deeper tan 1 inch over the bottom of the tank.
Next you add the liverock. Now you have 2 options.
Uncured. Cheaper but the tank will need to cycle fully. You will find that uncured rock can carry alot of mobile life forms that makes it a rich and diverse purchase indeed! Be prepared for a very smelly couple of weeks though whilst the Uncured rock cycles (it smells like rotten eggs
)
Cured. More expensive but it means you can add a fish right away (well cured liverock doesnt need to cycle as long as its removed from the shop and in your tank within a few hours (most people have it shipped overnight for next day usage and its still fine) WIth cured rock you wqill find less diversity of mobile life simply because it usually wanders off in the shops curing tanks
You will need 55lbs of liverock for a tank of this size. If you use Uncured then let it cycle and test daily with your tests kits until readings are zero.
If you use Cured then get your clowns and place them in the tank.
Other factors to consider...
Skimmer. Thisis an important bit of kit that will be needed if you are running the system i have recomended above. At first you will get away without one and if you are on a budget then this can wait a coupe of weeks. However, once the system starts to settle down you will find that running a skimmer is very good practise and will keep nutrients low in the tank.
External filter. This is not essential but very useful if you run one for the simple fact that you can increae the flow in the tank (always a good thing) and you can use the cannister to put treatments etc. remove and bioballs or ceramic media as its not needed and just use sponges in the cannister to clean the water. This cannister is also a great breeding ground for pods and seasquirts.
UV Steriliser. Again not essential but if you ever get whitespot and you dont have one then you will rgret it for sure. Expensive but well worth the money IMO.
Thats it for now really (i have probably forgotten something knowing me!
) ).
Lightning isnt an issue at the moment but if you want corals at some point then the members here can help you with this also.
Lastly, as you are keeping clowns I assume that an anemone is also on your list? I strongly urge against an anemone. They are very hard to keep and require strict water managment. Everyone thinks that Clowns need anemones to thrive but this is not true. Clowns will host in ANYTHING! My pair like to hang out in a leathermushroom coral and a Branching hammer coral even though a bubbletip anemone sits no greater than 3 inches from them
) Basically your future clowns cannot be "Made" to host the things you place in the tank. They will find a host if and when they feel like it
)
Hope this helps.
but can ppl tell me step by step how i should start from the begginng 
Thnxs in Advance 
