The following command backs up the 'Users' database to 'D:\DB_Backup' file. Its better to not give an extension.
BACKUP DATABASE Users TO DISK = 'D:\DB_Backup'
When you try to restore database from another server you might get the following error:
Error 3154: The backup set holds a backup of a database other than the
existing database.
In that case you should use WITH REPLACE option to replace database with the database from backup:
RESTORE DATABAS...
