Ok. The guy at the fish store is by no means unbiased. You need to allow your tank to cycle. Fish should not be added until you have disappeared spikes of Ammonia and Nitrite and increasing Nitrate. Do you have a test kit?
You will need at minimum a T5 lighting fixture and MH
would be better to keep a nem. Aragonite sand is the best substrate option IMO
, it doesn't need to be "live". It will become so in time. CC will trap wastes and cause problems down the road. Please read the stickies and articles.