I’d recommend the Moon journal pages from Mayo Dark Sky Park: https://www.mayodarkskypark.ie/discover/the-moon/
and an overview of the phases each year can be found on the Moon Calendar from spaceweek.ie (this is last year’s stay tuned for next year’s you’ll find it on the for teachers page).
So if you want them to observe in the evening, start a few days after New Moon when they can see a crescent moving towards the 1st quarter Moon.
Dates of new Moon this year are September 2, October 2, November 1, November 30 and December 30.
International Observe the Moon Night is on September 14 this year.