It is recommended that you use lbs of rocks per gallon of water. If you have a 10 gallon tank, it is suggested to use 15 lbs of gravel. Aquarium Pebbles / Rocks / Stones / Gravel from Pure Water Pebbles.
That is a good fish tank. The bigger a fish tank is the better. The cabinet underneath will be useful for storing all the food and accessories etc. that you need to run it. 330L Black Height Added Cabinet Aquarium Fish Tank Tropical / Marine 120cm 4ft with T5 Lighting All Pond Solutions