Start your flow with a trigger like "Manually trigger a flow" or "When a file is created". Add the "Get file content" Action:
In Power Automate, create a new connection using the File System connector, pointing it to your gateway and local root folder. The Flow Steps: Use SharePoint – Get file content to retrieve the data. how to download a file from sharepoint using power automate
Add the OneDrive for Business – Create file action. Use the "File Content" from the previous step as the input. Start your flow with a trigger like "Manually