The man is a really good place to start.
If you want more guides than the manual you can use thoses ones :
You will see, its really addictif.
- Intersting for gapps => Install i3 WM in Arch Linux based Distribution
- Intersting for the basic configuration => https://www.linux.com/learn/how-use-super-fast-i3-tiling-window-manager-linux
I cant recommend you enough to use compton (composer to avoid tearing) and browser such a qutebrowser (a full keyboard oriented browser ).
The terminal play a really important role in i3. I cant recommend enough Alacritty.
For the file manager you can still use your GUI, or something like ranger / midnight commander.
No problem, ping me if you need You will see, if you really want to go minimalist and well configured, you can easily have multiple terms, browser with several tabs open, for only 750 Mb of ram in total