Most LFS will offer this service for the simple reason that will bring you back in. What you must do is surf this site a little and draw on the wealth of knowledge that is this community, and want to fully understand what is happening in your tank. You'll want to get three test kits as soon as you can: Ammonia, Nitrites, and Nitrates. What you want to see, reffered to as the "cycle", is a spike of ammonia as your tank starts breaking down organics....then as you continue to test for ammonia, you'll see an increase in nitrites (less of a toxin to marine life than ammonia), and finally you'll see an increase in nitrates (a more manageable toxin, for the lack of a better word). Once you cannot detect ammonia and nitrites with your test kits, and only see a small amount of nitrates (< 25 mg/l) then you're tank has cycled. What you have created is a small ecological cycle which can make up for any lack of experience, or small mistakes on your part. Too many people, especially with nanos, make the mistake of jumping in with both feet in the deep end of the pool. Surf around on this site, check the FAQ. Good luck, and if you have any more questions just ask....there are plenty of nice people around here to answer your questions. We are all, hopefully, dedicated to this great hobby!!
