The i3 window manager is a lightweight tiling window manager for the Linux operating system. For more information about i3, check out this article: 5 reasons the i3 window manager makes Linux better. If you are ready to start with i3, check out Getting started with the i3 window manager on Linux.
The i3 window manager may seem hard to use at first because it relies on keyboard shortcuts for most operations. Use this cheat sheet to help you get around i3 when you're starting. This list includes the default keybindings to open and close terminal and other programs, navigate around workspaces, move and resize windows, and exit i3. Soon these shortcuts will feel natural and you learn how to define your own shortcuts to become even more productive with i3.