I remember reading several books on the subject way back when. A few were sensationalized but there were a couple that were very well written. Jim Jones penchant for having people listen to him goes all the way back to when he was a kid, he truly liked to hear the sound of his own voice.
I found the start of the movie already quite manipulative. The habitants of Jonestown are waked in the middle of the night by sirens and are ordered to drink something (which is the way they eventually commited suicide), but it turns out to be just a drill and they're okay. I had my doubts about a film about a serious subject that starts in a way that feels exploitative, but I don't know, maybe he rehearsed the suicide beforehand - the problem with such films is you can't tell what really happened and what they made up.