i had platies once a long time ago,i wasnt very experienced back then.well one day i was lookin in the tank and saw how big my female platy was getting so i got excited at the prospect of babies !!!!,but i was nt sure much back then,then one day i saw sum tiny iccle fish under and around the plants,i didnt have a seperate tank of breeder trap so i thought see how they go and i read to ground sum flake food down to powder.
or roll up a tiny ball of flake so it sinks,my baby platies would come out of hiding and go for this while the adults wud feed on the top.everytime i would do my routine maintenance of tank i kept finding more baby fish awwwwwwww.
but that said some did get eaten, but i did manage to end up with 2 new adult platies without seperating which can happen if you are lucky but if you wish to keep them all.what others have said transfer them to a breeder until they older or another tank.
good luck with your new babies,it is lovely to get babies