The diorama is not finished and represents two soldiers with one officer behind a trench,in the middle of winter, operation: Siege of Leningrad.
Painting the soldiers, finnishing toches for the snow, and adding more items are requiered for the diorama, but i learned about painting and not to rely on the camera flash.
So just use a light fixture kept above your head and maybe if its needed another one in the same position but to the left or right to disperse unwanted shadows.