Before using this feature, you have to set your MySQL dump binary path with the variable DB_DUMP_BINARY_PATH in the /.env file.
Example with MAMP on Mac OS: DB_DUMP_BINARY_PATH=/Applications/MAMP/Library/bin/.
Note: You have to set only the path, so without mysqldump.
If local disk is used, you can get the backups on your server in the /storage/backups/ directory.
Important: The /storage/backups/ directory is NOT the MySQL dump binary (mysqldump) path. So if you don't know your server's mysqldump path, you have to contact your host to get more information about that.
Go to the Admin panel -> Backups to make the backups manually.
Go to the Admin panel -> Setup -> General Settings -> Backup to schedule backups and their clearing up.
Go to this link for more information.