It’s probably worth mentioning that if you’re going to be programming the chips with a bootloader, you really want/need to purchase a usbasp programmer. As Pert mentioned, you might be able to do it with the FTDI usb to serial converter but it’s really not advisable. A usbasp can be had for a couple of quid from China in a few weeks and it’s simply not worth the hassle to try to do it otherwise. The usbasp plugs into the six pin ISP header on the Uno.
If you’re going to be installing bootloaders onto more than a handful of chips, it would be be worthwhile to purchase another Uno (or clone) and one of the “isp shield” that plugs into the Uno and has a 28 pin zif socket. That will save wear and tear on the chips and lots of time.