Hi lunahime, and welcome to AA!
You will find this forum very helpful, if you listen patiently, and do your own research as well. Advice given at a fish store can be slanted to trying to sell you more fish. I'm currently doing multiple water changes per week, because we listened to the salespeople at the fish store 3 years ago, and now we have a pleco in a tank that is way too small for him. We will soon have a new large tank for him, but until then, it's big water changes every other day. Just so you know what can happen. And it sounds like you need some information about how to cycle your tank, and we have all kinds of resources for that on the forum. Here's a link that may help you:http://www.aquariumadvice.com/forums...es-154837.html
Happy reading, and happy fishkeeping.