Honestly, unlike the other books in Studio Fun's in-universe journal series there is very little new info or character insights in this one. It basically recaps Shattered Empire, Poe's story from Before the Awakening, and TFA, with a very brief mention of events of the first story arc of the Poe Dameron comic book, all told from an in-universe point of view - communications, Poe's pilot logs, datafiles, etc. so if you've already read those stories there isn't much added to them. I think the biggest thing we learn is that Poe had his Black Squadron X-wing stashed at his parents' home on Yavin 4 and picked it up from there immediately after leaving Jakku. It's not necessarily a bad book at all, it's simply aimed at younger readers who may not have read Before the Awakening or Shattered Empire so set your expectations accordingly.