Welcome to AA! if your tank is brand new and you just added fish, be prepared to do daily water changes to get them through the cycle. if you don't know about cycling, read up on the nitrogen cycle, and buy a liquid test kit--your best friend! API Freshwater Master test kit is the preferred brand around here ($18 at walmart.com)
here are some links you should look at
Fishless Cycling For Dummies
I just learned about cycling but I already have fish. What now?!
there is some good tips in this thread, too Common Newbie Pitfalls
this forum is a great resource for info, just explore and learn all you can!