If you have the Professional version, this must be done on the server machine. If you have the Enterprise version, you will need to create the backups using your SQL Server Management Studio.
To backup the database in InventoryControl, click Administration, Backup. It will prompt you for a filename, and will fill in a default filename of InventoryControl<date stamp>.bkp. You can change the filename if you like, then click OK to create the file.
The file will be located in C:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\Backup. (If there are multiple SQL databases on the machine, this may be MSSQL.2, MSSQL.3, etc) To change the backup directory, you can go to Tools, Options, SQL Server Backup Location and enter a different path.