Google Classroom is a virtual learning environment. Teachers can upload material, and set you questions or tasks to do. These can often be done, and then marked online, giving you feedback efficiently.
You'll know if you have an assignment in google classroom, as you will have an email telling you it has been set.
From a Computer
From any computer (Windows / Chrome / Mac) go to RMUnify.
Once you have logged in, use the Google Classroom tile (pictured right).
If you have a choice of accounts, use your school sbllearning account.
If you are asked to add an account, add your school sbllearning email address
You will then see all of your different classes, and you go click into them to see what work has been uploaded or set.
On Phones and Tablets there is a dedicated Google Classroom app (Android and Apple), which you can find in the app store. Once downloaded you can log in and will be able to see any work that teachers have uploaded or set.
How to upload work to classroom
Have a look at this video - https://youtu.be/STRgCq-yVaQ It talks about uploading a photo but is also relevant to uploading a word document or power point to google classroom.