Convicts are great first cichlids to keep. You can use either a sand or gravel substrate, and some rocks would be nice to establish some territories in the tank. I wouldn't do
driftwood, because it tends to soften the water, and cons tend to like harder water. Plants are definitely out since the cons will make lunch of them, lol. You can look at my CA tank if you click on my signature. Cons would probably do well in a tank similar to the way I decorated mine. If you want to keep a group of four or five, try to get all the same sex. If a pair forms, unless you have a larger tank, they won't tollerate other fish.