Connect a USB slave into Arduino using FTDI
No, that is completely wrong.

In USB you have hosts and devices. A device has to connect to a host. Your FT232 is a device. The barcode scanner is a device. Both of them need to be connected to a host for them to do anything.

So you need a USB host shield to act as that host.

However - check the manual for your barcode scanner: it may well have a RS-232 mode that it can be switched into (may need a different cable attached).