If you need to work in a group your lecturer may set you up with a group in Office 365, any groups you are in can be found in the left hand side of your Office 365 webmail.
Your group will enable you to have conversations and share files, clicking on the conversations tab will take you to the conversations area (this opens by default when you go to the group). You can click on 'Send Email' to create a new thread
Or reply all to reply to the thread you are on
To access the files in a group click on the files icon
Clicking on the New tab will open a menu that enables you to create a new folder, Word Document, Excel Workbook or PowerPoint presentation
You can also upload an existing document from the files on your computer
If you create or open a Word, excel or PowerPoint, these will open in Office online apps, (in your internet browser) which means they can be edited straight in your browser, they are then automatically saved to you group files and you can also work collaboratively in real time on these documents.