New Cichlids Tank set up

[fishowner3]

Very new to cichlids and have decided to set up a 42 gallon tank up to fill with them. I currently have a 10 gallon set up with 2 turquoise jewels, a demasoni, and a pleco. They will be moved to the 42 once set up but before setting it up I need suggestion on whether to use sand or gravel. And what other types of cichlids I should fill the tank with and how many I can house. I really enjoy watching them breed and raise there fry and my LPS pays decent for the babies so what do you think would the best ones to have and easy at reproducing. Also what should I use for decor and how long should it be ran before introducing the fish to the tank

 

[V227]

Upgrading to a 42 gallon tank from your 10 gal. Is a good move. Although much larger, the new tank is still rather small regarding a Cichlid setup. IMO African Cichlids are not really suited for a small tank, unless you just keep a few shell dwellers. They typically are hyper aggressive in a large tank and that aggression likely would be amplified in a small one.
Research Dwarf Rams, German Blues and Bolivians. Both types are quite colorful, and given the correct water parameters readily breed.
As for substrate, I use very small grain gravel (pool filter gravel). It seems that the growing trend is sand. I've seen some beautiful tanks posted with sand substrate.
Your going to need a good power filter and heater. When the time comes be sure to ask questions regarding those items.