I downloaded Ubuntu recently and now I have a .iso file. What’s the best way of handling and opening those files?

An ISO file is a disk image, meaning it’s a copy of the entire contents of a CD or DVD. There are a couple of things you can do with this file; for example, you can open the ISO file and extract the individual files from it. I like using a program like 7-Zipp to do this. So, for example if you had an ISO file with the best work Philly had to offer; and didn’t want to waste a DVD, you could point 7-Zip at it and just extract the file you’re interested in.

The thing about Ubuntu is that you will need to boot from the disk image, rather than extract files, and the easiest way to do this would be to burn it to disk. You can use software like the ISO Recorder to do this. It’s a straight-forward (free) application that takes you ISO file and creates a disk with it, allowing you to boot right off it and install Ubuntu on your hard disk.