Be aware that you'll lose any changes you made since the backup was created. What does it mean to overwrite a file?: Restoring a backup file replaces your current data with the data stored on the backup disk. After naming the file and selecting the location, click Save, then click Yes to open the restored file.
The Quicken backup file has the extension.
Select Restore from your backup, then click Browse.Select the File > Backup and Restore > Restore from Backup File.