Hi, I'm Rodrigo and I will help you.
If the files are saved on OneDrive, you only need to enter the OneDrive application on the new computer using the same account, If you want to sync and the user folders (Desktop, Documents, Pictures), right-click the OneDrive icon on the right side of the taskbar > Settings > Sync and Backup > Manage Backup and turn on the backup options.
If you want to delete or change the files from the old PC at any time, make sure to disconnect the account, otherwise, the files will sync and modify in the new PC too.