only tried with premixed falafels so far, but i usually just put them for like 20 Minutes at 180°C in the oven. just gotta flip them after ~10 Min.
I don't think you can really mess them up too much, it's probably also fine if you use lower heat or keep them shorter/longer in there. you can also just taste them from time to time to see if they are good.
You can add oil if you want, i bake them without though