If you're new to OS X Mountain Lion getting started is simple. Just follow the instructions provided in this free lesson.
Mountain Lion allows you to use many different multi-touch gestures with your mouse or trackpad. These include pinches, taps, double-taps, and swipes. Each gesture performs a specific task, and by learning different gestures you can increase your productivity.
In order to use multi-touch gestures, you will need the right equipment. If you have a laptop, the built-in trackpad can be used. For desktop computers, you can either use the Magic Trackpad or the Magic Mouse. One of these may have been included with your computer; if not, they can be purchased separately. Most mice are not touch-sensitive and cannot be used for multi-touch gestures.
From left to right, the images below show a laptop trackpad, a Magic Trackpad, and a Magic Mouse.
To see gestures in action, watch the following video from Apple.
Some gestures will vary depending on whether you're using a trackpad or a Magic Mouse, and there are a few that only work with trackpads. Some apps may not support all gestures, but apps made by Apple (such as Safari) tend to use them more. Therefore, you may want to practice the following gestures with Safari before you try them with other apps.
There are many more gestures you can use. To learn more, check out the Mac Basics: Multi-Touch Gestures page on the Apple website.