Shagreen, working with?

I am interested in using shagreen as a finish to a knife handle.
I have the shagreen, but can anyone out there tell me how to use
it. Do I soak it/ boil it? Can I shape it? Can I bleach it - it
is currently a king of brow= n colour with white areas showing
through the tops of the brown ‘beads’. How is it dyed?

Look forward to hearing from you.