As you look through this site, I want to encourage you to shift away from thinking about how to use an app like Google Classroom in your class and focus more on this question:
In your ideal classroom, and especially for the lesson you are about to teach, what do you want your students to be doing?
In the Ideas for My Lesson page, I have tried to arrange the tips in a way that would support your realizing that goal. If you just want to learn more about some apps, though, that's there, too.
If you would like to schedule an appointment with me, schedule it on the app: tinyurl.com/phstechapp. If you are looking for an answer to a problem, try the Help! tab.