why do you think the author showed German soldiers, such as Hans Hubermann, performing civillian tasks instead of being shown on a battlefield? and why did he focus on ordinary German civillians during wartime?

This novel isn't about battlefields; it's about the people. There was far more to the war than battles. The decision to write this novel from a civilian standpoint makes it more human. In it we experience the hopes, fears and suffering of the people who don't wear uniforms.

The author's portrayal of Hans Hubermann and other German soldiers as engaged in civilian tasks rather than on a battlefield is likely a purposeful choice to highlight the human side of the war and the impact of conflict on everyday lives.