Google now has added a Google Chrome extension called Training for Google Apps.
This extension is an interactive training and walkthrough within your Google Apps. This will help train you with apps such as Google Classroom, Gmail, Google+, Calendar, Sheets, Slides, Docs, etc.. This in-app experience allows you to learn while you are in the program. You can also learn more at Google Help Center. Once you install the extension it will show up like this:
You can then click this trainer button at anytime when trainings are available and be instantly trained on a specific task right within the application. Please see a couple examples below.
Here is another example in Gmail:
If I open Google Drive and click on the Training button:
If I open Google Classroom and click on the training button:
This is a great way to get up and running with any Google Apps!