Share the class code with students and ask students to join. (recommended)
Go to "People" tab and invite people individually through email address.
Reminder: If you use this method, students or co-teachers need to accept the invitation on their Classroom dashboard.
Click the announcement text box under "Stream" tab.
If you have the same message to post in different classes, you can choose multiple classes. And select students who will receive the message.
You can set the due day for the assignment, and students will get reminded on both Google Classroom and Google Calendar.
Click "View assignment" to check submission status, view submitted files, or leave comments to their work.
You can add topics to your post and reorganise posts by dragging and dropping.
All the materials that you published, together with students' submitted documents will be stored in the default GDrive folder. You may click the "Class Drive Folder" icon to access them.