Install the add-on from the Google Workspace marketplace. After that open a Google Sheet, select Extensions → Drive Explorer for OneDrive → Launch.
Wait for the sidebar to fully load. Then, click on the Authorize OneDrive button to give access to your OneDrive.
After successful authorization, select Pick from OneDrive to open the OneDrive file picker to select the folders from which you want to fetch the files.
On the interface, add or remove folders as needed. When ready, select Fetch files.