I'll try to make my instructions easy to scan, but also as specific as possible. How to set up an aquarium. Get yourself an appropiate size aquarium for your needs. Start by adding warm tap water but you must use a water conditioner to remove chlorine and chloramine from the tap water.
You'll need at least 1 lb. of gravel per gallon of water, make sure you rinse off the gravel thoroughly. There is a product named cycle which is a bacteria to start you're aquarium's system off, this product is a benificial bacteria to help establish you're tank.
Start up you're filter's and heater, the heater should be set at 78 degrees farinheit. Let the tank run for at least 24 hours before purchasing any fish. 
This is a picture of an unplanted Aquarium Always make sure your fish are compatible, ask the sales person at time of purchase. Once you've completed putting in the gravel you can add plastic or live plant's, for live plant's you'll need florencent lighting to imatate the sun's spectrum. Float your fish in the plastic bag they come in for at least 20 minutes and no longer than 30 minutes, but when taking them out of the bag do not put the bag's water in your tank. take the fish out with a net as to not transfer any disease to your tank. That's basically it for starting up a new aquarium hope this information helps you. | 
