https://www.howtogeek.com/188530/a-windows-users-guide-to-mac-os-x-keyboard-shortcuts/
A Windows User’s Guide to Mac OS X Keyboard Shortcuts
Keyboard shortcuts are essential for being productive on any device with a keyboard, whether it’s a Windows PC or a Mac. Use these keyboard shortcuts to get around your Mac more quickly.
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1. Click and hold the green button. Your window will get a bit smaller. It's ready to enter split screen mode.
2. Stop clicking and your window will move to the left half of your screen or monitor.
3. On the right half of your screen, the other windows you have open appear. Click on the one you want to view.
4. Your second window will pop into the right side of your screen. If you want to switch sides, simply drag either window to the other side from the menu bar of either window.
5. If you want to make one window wider or narrower, click the border between your two windows. Drag your cursor to make one smaller and one larger. Your two windows will still fill the entire screen.
6. Your menu bars, including the red, yellow, green dots, disappears in this mode. Move your cursor to the top of your screen and the menu bar reappears over both windows.
It's easy to toggle back and forth between two documents in split screen view. You can also toggle between your split screen and other apps. Just use Mission Control or swipe left or right on your trackpad with a multi-touch gesture.
excit split screen mode :
slide your cursor up to the top of the screen until the green button reappears. Click to reduce the size of your window. The window you're in will revert to its pre-split screen shape. The other window will go into full-screen mode.