Tilapia are actually pretty easy to start with, but you should get them as adults. They will be a bit bigger when you get them. They need to eat, and they eat a lot. You want at least one male and one female. Males will fight for a harem of females, so you want to make sure you have at least one male and one female in your tank. You will also want to add a few more plants than that, but I'd say about 6-8 is a good number. The most important thing is to get a really good water conditioner like a Marineland, AquaClear, or similar product.