So, much like the reports made by Generals and commanders in the 1700's and 1800's saying things like "this unit moved here"..."Attack was repelled" etc. Are there any known entries like this from the Roman era? Well understood and translated ones?
Although obviously in a different style, most Roman primary sources that cover battles will give a play-by-play of the battle, although if you're not familiar with the style of writing can be hard to understand and probably the closest to an actual after-action style report would probably come from Caesar's conquest of Gaul as it is written by the man himself about, surprisingly, his conquest of Gaul and the battles that took place there.