###Working with multiple files
:e filename - Edit a file in a new buffer
:bnext (or :bn) - go to next buffer
:bprev (of :bp) - go to previous buffer
:bd - delete a buffer (close a file)
:sp filename - Open a file in a new buffer and split window
ctrl+ws - Split windows
ctrl+ww - switch between windows
ctrl+wq - Quit a window
ctrl+wv - Split windows vertically