Over the summer Google Classroom greatly increased your options to customize notifications inside Google Classroom. This is great since you may want to receive notifications when someone mentions you in a comment or post, but you don't want one when someone resubmits an assignment or a similar function.
Thankfully Matt Miller, from Ditch the Text Book, has just posted an excellent article on how to manage all those Google Classroom Notifications. Check it out here:How to manage Google Classroom like a boss with notifications.
To learn more about setting up filters in Gmail, check out this blog post.