How edit files into vim:

-> ls and press Enter to list the contents of a particular directory 
-> cd .. or cd filename(s) and press Enter to change to another directory (as in DOS) 
-> sudo - to authenticate yourself a superuser to gain extra security privileges 
-> vim filename to open a file in vim 
-> i key to start editing the file 
-> press Esc key then type :w and hit Enter key to save a file in Vim 
-> press Esc key then type :x and hit Enter key to save a file and quit Vim  
-> pressing the Esc key (pressing the Esc key again does nothing if you’re already in command mode) 
-> :wq and press Enter to write the file to disk and quit vim  
-> :w and press Enter to write the file to disk without quitting  
-> :q and press Enter to quit vim without saving the file 
-> :q! and presa Enter to exit a file opened with read-only

Example:

sudo vim /Library/Preferences/VMware\ Fusion/networking

I will update when I need and lear different things about vim.