To open Task View, simply click the Task View icon next to the Cortana Search Box, or hit Windows key + Tab. You’ll see all your open windows so you can easily switch to a different one; or, at any time hold down Alt and press Tab to toggle between all your opened apps.
When you hit Windows key + either of the side arrow keys, you’ll enable Snap – a feature that snaps one window to exactly half of your screen. Snap Assist will automatically show you your remaining opened windows, so you can choose which app to fill the second half of the screen.
To view even more, try using Snap for up to four windows at a time. Just drag a window with your mouse into any corner of your screen.