To access your group's file directory through SharePoint directly from the browser, follow the steps below:
Access the Groups list in Outlook Web or Outlook for Windows: In the left sidebar of Outlook, scroll the bar to the bottom and click the Go to Groups (Go to Groups) option.
Select the Group and Open it in SharePoint: In the list of groups on the left, click the desired group. In the group panel on the right, locate the top toolbar and click the SharePoint site icon (the green "S" icon).
Navigate to the Documents folder: A new tab will open in your browser, taking you directly to the group's page in SharePoint. In the left sidebar of the page, click the Documents tab to view and manage all of the group's files.
You can bookmark the address of the desired SharePoint site for quick access.