Tap and hold down (i.e. long press) on the row after which you want to a piece of history. It will then give you the option to add a Period, Event, or Scene, depending upon context. There are a few stages of the game where you’re asked to do something else (like choose a Focus) so adding history is disabled for that step, but you should be good to go if the game stage is First Pass, Make History, and Explore Legacy.
Thanks Brian for your suggestion and interest. I’m in the process in gauging interest in an Android version (others have mentioned it as well). An iPad version is also on the list. I’ll have an update in April on the potential availability.