Hi and welcome to the forum
If you contact your water supply company (via their website or by telephone), you can ask them what the general hardness (GH) and pH of the water is. This will help when it comes to choosing fish for the tank.
If you can tell us the tank dimensions (length x width x height) that will also help us advise you on suitable fishes for the tank.
Does the tank have a filter?
If yes, can you tell us the brand or post a picture of it?
Do you have a stand for the tank, and gravel, lights or anything else?
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There are several ways to start an aquarium. One is to have fish in the tank while the filters develop beneficial bacteria that keep the water clean. The other is a fishless cycle where the tank is run without fish for a month or so while the good bacteria develop in the filter. A fishless cycle is easier on the fish but it means not getting any fish for 4-5 weeks.
There is more info on fishless cycles at the following link.
http://www.fishforums.net/threads/cycling-your-new-fresh-water-tank-read-this-first.421488/
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Most fish health issues are caused by too much food and not enough water changes. The following link has some information about what to do if your fish ever get sick. It is pretty long and boring but worth a read when you get some spare time. I suggest printing it out and reading it in be to fall asleep.
http://www.fishforums.net/threads/what-to-do-if-your-fish-gets-sick.450268/
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If you go to the local pet shop, make a list of the fish and plants you like and then post them on here. We can go through the list and suggest things that are compatible.
If you have any questions, just ask and we will do our best to answer them for you.