It sounds like File History on your new laptop is currently set to back up your new files instead of restoring your previous backup from the external drive. Here's a simple way to switch it so you can get your old files back:
First, disable File History temporarily on your new laptop to prevent it from starting a new backup. You can do this by going to Settings > Update & Security > Backup and turning off File History. Then, open the restore interface by clicking the Start button, typing "Restore your files with File History", and selecting the matching option. This should open the File History restore window and automatically detect the backup on your external drive.
Once you're in the restore interface, navigate through the folder structure to find the files you want to recover, then click Restore to copy them back to their original locations on your laptop.
If you prefer a more manual approach, you can also use File Explorer to navigate to the backup folder on your external drive and copy the files to your desired location. For more details, you can check out the official Microsoft guidance on restoring files with File History here: https://support.microsoft.com/en-us/windows/bac...
Could you let me know if these steps help or if you encounter any issues along the way? I'm here to help further if needed.