You can restore your previous backup-a file from mobile as well as drive, if you have taken backup of application before.
Follow below steps:
>>Click on Restore option in backup and restore icon.
>> Then select drive or mobile where you have taken backup before.
>> If you are restoring data from drive then select file name(xyz.db) which data you have to restore.
>> If you are restoring data from mobile then select file from sales assist database folder.
Note: Once you restored data, then your current data will loss.So make sure to take backup of this file before restoring any other data for security purpose.
Please check attached video.
Restore Data from Mobile
Restore Data from Drive