You need multiple playthroughs. There is a day limit. You need to advance girls plot to a point before a certain day when an event happens. Then you pick one of the girls you've completed the events for and get their scene. You only get to pick one so you can save at the selection screen to see the others. No idea how seeing their scene specifically will affect things down the line as it seems you can still continue with other girls anyway but since chapter 2 only has a little bit of content currently I have no real idea.
Viewing post in My Girlfriend's Friends comments
It's not so bad, there's barely any average plot. Just the opening and the main part of the event scenes. Otherwise it's just chasing the girls of choice so it's not like you'll be stuck rereading large sections or anything. Apparently a harem route might be possible in the final version but I think that was just mentioned in passing at some point. It would be nice to just trigger the event when I feel like it instead of having multiple saves but it's merely an inconvenience at this point.