You already know this tune. Every playground on earth does, and that is exactly why it makes a good first French song: the melody carries you, so your ear is free to notice what the words are actually doing.
Two things worth noticing. First, the question - ? uses the formal vous form, sung to a monk - French politeness reaches even into nursery rounds. Second, matines is the pre-dawn monastic prayer service, which is the whole joke of the song: Brother James is the monk whose job is to ring the bells that wake everyone for matins, and he has slept through them. It is an old word you will rarely meet again, and you do not need a flashcard for it - the song will hold it for you.
The tune, by the way, has been sung in France since the 1700s, and recent archival work credits it to Jean-Philippe Rameau, one of the great French composers. Not bad for four lines about a monk who overslept.