Linux OS

I've done some more research on the different "distributions" for Linux. I found three others that sounded better, but I can't find out how much hardware is needed. And I can't figure out how to download. One has to get them from either a ftp site or a "mirror" site. Many moons ago I understood how to ftp, but no longer. When I went to mirror sites, I wasn't sure what to try (a folder or each item within the folder) Even found one distribution that can be run from a stick, however, the Gateway doesn't have any USB ports. I've given up on trying to install a Linux operating system on the old Gateway computer. It's just too old.