If you're running windows, you'll want to go to the control panel, and to Fonts. It'll bring up a folder up all the fonts you have installed on your machine there. Just drag and drop your new fonts (unzipped and out of folders) into the folder and restart photoshop. They should show up on the list not only in photoshop, but in your word processors and other apps too.
If you're running a mac, which I am not familiar with at all, you'll want to take the same approach and install the fonts universally, not in photoshop.