Use a Microsoft 365 Group as a Guest
Action
If you have been invited to join a Microsoft 365 Group as a Guest, follow the steps below to accept the invitation and join the group.
Instructions
You will receive an email welcoming you to the Group:
To access the group and its files, click Go to SharePoint:
If you do not have a Microsoft account yet, you will be prompted to create one. Click Next:
Create a password for your Microsoft account:
Verify your account with the code sent to you:
Complete the CAPTCHA if prompted:
Review and Accept the permissions:
You should now be able to access the Group Document Library (files). If you get an error, try closing the browser window and clicking the link from the invitation email again.
Visit Microsoft's documentation for more info on using an Microsoft 365 Group as a Guest