There are very few reported cases of otos breeding in the home aquarium. I don't believe it is because it is extremely difficult to do however, more like people either didn't do it on purpose, or just didn't bother documenting it.
When doing a pwc add water that is cooler then tank water, this should induce spawning behavior.
Eggs are small and transparent jelly-like masses which will cling to whatever surface they were laid on. Most will be laid on plants, leaves and stems. Sometimes they are laid on the glass of the tank walls, but those ones don't always hatch, either they get eaten by other fish in the tank, or sometimes they grow mold from being exposed to the brighter light.
Hatching takes around 2 days, after which you can see the fry hanging on the glass and darting around much the way the adults do. Adult otos will not harm the fry, so there is no need to remove them once the eggs are laid. As long as you have a mature tank with plenty of algae, you do not have to worry about what the fry will eat, they'll have plenty of food for a while.
Is it super difficult? I don't want to, I plan on trying to breed fish later down the line when I have more experience... but for now I am just curious as to why nobody "tries" or has been succesful at this. It seems they would probably be a lot more hardy of a species if they could be bred in captivity. Less stress on the poor things.
