HI and welcome to the forum.

Well if you don't know what your looking for, we should?? J/K
Ok with the convicts, the "guppies of the cichlid world, when it comes to breeding, eggs will be the first things to show up. They will be white when first laid, and the viable ones will turn a biege in colour. I am not sure on how long it might be before they lay. Sometimes they practice the nest building, and then seem to forget about it. So just check for eggs, once you do see them, then you can keep an eye out for them becoming wigglers, and then fry. It happens pretty quick, a matter of days from the egg laying untill you will have free swiming fry.