Installing new fonts on a Mac involves downloading font files from online sources, decompressing the zipped font files, and then double-clicking the font files to install them. Once installed, the fonts will be available for selection and use in applications like PowerPoint and Word. The document provides step-by-step instructions for finding fonts online, decompressing zipped font files, locating and installing actual font files, and verifying the new fonts are available in font selection menus after installation.