How do I split a window? Or am I blind of the options

[rawxtl]

I want to know if you can split windows in focus, so far I haven't seen any option to do so. Or do I need to bind a key on the config file, I haven't touched the configuration file yet.

[obiwanus]

If you're on the latest stable 0.3.8 you can only split the window in 2 parts. This can be done by holding ctrl when opening anything, then it will open on the side. Also it's possible to choose a side by Ctrl-1 or Ctrl-2 by default.
All of this can be found by reading the global config's key map.