I would reccomend the following two primary source publications as examples: Alfred Kelly, The German Worker - a collection of autobiographies This is one of the best, if not THE best, primary source book I have ever read. Helped convince me that I wanted to be a historian of Modern Europe. The introduction by Kelly is a huge part of that - he gives context about the situation in Germany over the period covered, explains the history of socialism in German-speaking countries, offers information on gender roles and expectations, class politics etc. I believe the lesson to take away is that providing your reader with different levels of context is key - what was happening in their country? Their region? In your case, what was going on elsewhere in the war? How does the rank of the person affect their experience? etc. Also, Willy Peter Reese's A Stranger to Myself should prove useful. It is a WWII diary, so the nature of the introduction should offer some war-specific guidance.