Looks good for the start of shading.
German WWII field gear is a unique mix of things.
The cylinder is a thin sheet metal can for the gas mask. They are a dark green in color (painting the can MM steel, and using a thin wash of black-green is good). it hangs on a leather strap that runs from NATO black to grey-geen, to a dark chocolate color. I hangs odd, too, the strap attaches just under the lid of the can, and then at the base, the mask inside makes it heavier towards the top, so it can form a sort of "inverted "7" or "L" shape when slung.
The canteen (water bottle) is covered in leather, the cup is a dark panzer grey. The strap goes all the way around, and is how the item is fastened as well as holding the cup on.
The rectangular item with a wedge shape section os the "bread bag" or knapsack. The narrow edge goes up, as there are two straps which fasten it to the belt. Color is a khaki or sage green, or even a buff sort of color.
Artillerymen, especially anti-tank gunners have to dig--so they should all have an entrenching tool. Since the shovel is used a lot, dig through you spares box for e-tools that do not have the bayonet strapped on over it. The blades of the shovels are black-green, the handles very dark gunstock, the carrier is leather lined fabric which will be a medium-dark green--feldgrau over black is good).