Google Classroom is a free web-based platform that integrates your Google Apps for Education account with all your Google Apps services, including Google Docs and Google Calendar.
When you set up Classroom it automatically creates a Classroom folder on your Google Drive as well as assignment folders - talk about organized! When student join your class, they also get a Classroom folder. Teachers can create assignments, announcements and questions to post to their class. Each of these can also have attachments - so you can include documents, links and videos for your students. Students can attach items to turn in to the teacher and everything is done online.
I've gathered a few videos and put them in a playlist to get you started - Google Classroom Playlist.