Once you have one app open, you just need to hold down the task switcher button in Android N to enable the split screen view. The app you're viewing gets pushed to the left, and any other apps you open show up on the right. Once you're properly multitasking, tapping the task switcher quickly lets you hop between apps on the right side of the screen. Each app takes up half of the screen by default, but you can adjust their width with a slider in the middle of the screen. (And yes, it sure does look similar to Windows 8's "snap" multitasking feature.)
In portrait mode, the split-screen feature moves apps to the top and bottom of the screen. While it's nice to have that option, it's honestly a lot less compelling than having apps run side-by-side in landscape. But I wouldn't judge Google too harshly though, even Apple and Microsoft haven't managed to make portrait multitasking a great experience. (Or maybe portrait mode is simply best suited for full screen apps.)
As someone who was pretty disappointed by the Pixel C, I was surprised by just how much the addition of decent multitasking changed my experience with it. Instead of feeling like a perpetually limited productivity device, Android N's split screen feature makes the Pixel C feel more like a full-fledged PC. I was able to write this post on one side of the screen while browsing on Chrome on the other, for example. I could also chat with my friends on Hangouts while trying to catch up with email. These are basic tasks for any computer, but it feels like a whole new world for Android devices.
Google was undeniable inspired by Samsung's split-screen app implementation, but it's in good company. Even Apple seemed to lift some ideas from its Korean rival when it came to iOS 9.
There's certainly room for improvement. I'd love a faster way to swap apps between the left and right sides of the screen. And I hope that Google adds some keyboard shortcuts eventually -- just imagine moving around Android with the swiftness of hitting "Alt + Tab" on Windows.
The Pixel C is still a problematic device, to be sure. But it's at least far more usable with Android N. And now that Google is offering it at a 25% discount, it's now a much more compelling Android tablet.