If it is the image that i think with the two braids that look like three I would start by:
Seperating the hair from ear to ear. (pin this TOP section out of the way)
Then divide the two sections that you have at the back in half vertically. ( like two french plaits)
Tie the left side out of the way. Start a french plait on the right bottom section using smaller sections as possible.
Then start from the top right side of your head at the front only taking sections from the front and do a french braid all the way to the center point. when you reach the middle of your head start taking sections from both sides as you work your way diagonally down from right to left.
I hope this is what you were asking and I havent just commented on something irrelevent. lol
I wouldnt be able to atttempt any style of that sort on myself it would end up very messy. I cant get my hands to the back of my head without my arms aching :-)