The best way to start is reading the documentation of the project. For example, the docs of i3 (a tiling window manager) are pretty good.

You could do a live USB of Manjaro i3 to test it before installing, that specific disto even comes with basic instructions on how to use i3 written in the default wallpaper. Then start hacking away the config file, and when comfortable, replace the i3 status bar with polybar, which also has great docs and lots of examples.

Trial and error is a good way to learn, and in a live USB you don't have risks*, except losing everything after rebooting, in which case you could try to run the OS in VirtualBox.

Luke Smith in YT has some pretty good videos explaining stuff.

*as long as you don't do something very silly, like mounting your drive and formatting/repartitioning it, or trying to install the distro where your actual OS lives.