First, I sketched the drawing, just the important details..
Then I wet the paper ( Arches 140g) and used mainly different shades of brown-Alazarin red,burnt, umber,Gamboge for the reddish browns and added sepia for the dark browns and added indigo for the darkest shade that is almost black.
I also used masking fluid to save the highlights. Its actually faster this way.
Just continue adding value and color to the painting :-)
I also applied a little bit of salt for texture...