You can create a class to assign work and post announcements to students.
If your school has a Google Workspace for Education account, you should use that email to create your classes.
Using a PC, follow the steps below.
Create a class
At the top of the Classes page, click Add 
Create class.
Note: If you don’t see Create class, your account only lets you join classes. Switch accounts or contact your Google Workspace administrator for help.
- Enter the class name.
- (Optional) To enter a short description, grade level, or class time, click Section and enter the details.
- (Optional) To add a subject, click Subject and enter a name or click one from the list that appears when you enter text.
- (Optional) To enter the location for the class, click Room and enter the details.
- Click Create.
Classroom automatically creates a class code that you can use to invite students to the class. You can always get the class code at the top of the class stream.
Problem creating a class?
- If you have a Google Workspace for Education account but can't add a class, your Google Workspace administrator might need to verify that you’re a teacher. Contact your administrator for help.
https://support.google.com/edu/classroom/answer/6020273?hl=en&co=GENIE.Platform%3DDesktopfor for more Google Classroom help.