When students log in, show them where they can go to find out more. There is a "Student help & resources page under their name in the top right corner of the site. As a teacher, you can also see this page under your own initials.
The student starter guide is worth their time to read and is excellent for parents too. As you can see, there are other resources that will help too. Feel free to email these resources to parents, but it can be just as easily downloaded from this help page.