I strongly second Leadfingers' recommendation; it's a great read.

But again, if you're serious about writing about an infantry soldier in a line regiment in that campaign, focus on finding sources from not only the unit in question, but also that brigade and division. If you are as new to military research as I infer, learn how the Eighth Army was organized and what the Cornwalls were doing within that structure. That info will steer you to other regimental histories and memoirs pertinent to your story.

Popski's Private Army was a Special Forces unit with a culture very different from that of a battalion of line infantry.