Sisterlocking uses a precision parting grid of which there are several patterns to choose from and a special tool that intertwines the hair into its locking formation.
You can start sisterlocks with hair that is relaxed and not completely natural. You can also start sisterlocks with any length of hair. Because sisterlocks are so skinny, the end result is that you hair will be very flexible and easy to style, just as you would your regular hair. You could have as many as 400 locs and you will not need to use any special product on your hair during the process.
You will not be able to start sister locks yourself. And, unless your best friends can do it for you, they can cost in to the 1000's of dollars to be done professionally.