i thought since it was really simple.. i could do it just by eyeballing mostly everything..
this is what happened :
the shapes aren't well defined, and it looks really confusing.. so i restarted and paid more attention to shadow shapes and colors and values. and this is the result :
hmm. i went too light in the middle of the page but it's cleaner now.. and i like how the light on the left side of the page looks correct :)
gotta do more of these rawrrr!