Follow these navigation steps:
- Go to OneDrive
- Click "Return to classic OneDrive" at the bottom left corner of the page.
- Click the Settings button (the gear icon) at the top right corner of the page.
- Click "Show Ribbon" from the drop down menu
- Select the file you wish to setup notifications for and check the box to the left of the files.
- Click the "Files" tab located at the top left of the page.
- Select the "Alert Me" icon on the ribbon and click "Set alert on this document"