If you want to keep the fry, I suggest investing in a breeder net. Its just a mesh cube with a plate at the bottom/top that the babies can get through, but the parents can't.
Also, I found when I had guppies that at around 1cm in size (maybe a little bigger) that the males will try to breed with the females, so separating them was essential to the females' survival (its not good for them to be giving birth so small) I'm not sure if plattys are the same, but its something to keep in mind.
Also, welcome to mfk, the people here are really nice and always happy to help, you picked a great forum to join.