Can someone help me?
Mange, Manges, Mangeons
Can someone tell me why these only work in some sentences and not the other? Is there a specific meaning or something?
French conjugates verbs (English too, but not as much, I eat - he eats.), so it's the form to use with certain pronouns.
Different verbs can be conjugated differently though, so you should check the tips and notes for the lessons for more information on it.