Hi, Struggling - I added a bit to your thread title to try to alert the people who might be able to answer your question, and I'm posting this message to bring your thread to the top of the heap.
Can't say I'm much on music theory - by triple meter, do you mean 3/4 time? By chant for children, are you looking for Gregorian chant or for something more like "neener, neener, neener"?
Best of luck to you in your struggle.
-Joe Offer-