Yayyy I'm so glad you got a tank. what size is the tank? did it come with a heater and filter? Now that you have an actual tank it's critical that you get a test kit, most people like API's liquid master test kit, its tests for ammonia, nitrites, nitrates, and pH. Now that you have a tank you must cycle it, some people use a fish less cycle, and others use fish. Its a matter of preference because the cycle can be very hard on your fish and some don't make it. You will need to keep a close eye on your tank parameters and if the ammonia or nitrite levels get to high do a water change. I recommend that your changing 15-20% of the water at least every other day, it may take longer for the cycle to finish but your fish doesn't die. Here is a link that tells you everything you need to know about the cycle http://www.fishforum.com/freshwater-...ium-cycle-252/
A cycled tank will read 0ppm Ammonia, 0ppm nitrites, and 5-40ppm nitrates. Nitrates are good so long as they are left in the safe range. from 5 to 40 and 5 being kinda low and 40 being kinda high. So if you notice a lot of nitrates a large water change will solve that problem.