Cover the baking sheet with parchment paper (or a special mat) put the bananas in one layer put in a preheated oven (I have around 190-200 degrees) for a time that depends on the temperature and how toasted you want to see the chips. It is advisable to turn the chips at least once during cooking (but not necessarily), approximately bake the chips for 20-25 minutes, until they are crispy. Watch out for chips, as they can burn (you can do it and not very crispy), in general, the moisture should go away.