baby platies!

hi i need help here urgently!! i just purchased 2 platies from the local LFS today and when i got home i realised that there are baby fries in the bag!! one of the platies just gave birth when im on my way home!
unfortunately not all survived... 9 died and im left with 8 baby play fries

so my doubts are..

how do i rear those baby fries??
and what neccesary equipments are required?

not sure if correct but here's what i did.

i filled a tank with all the water from the bag, den i added new water conditioned with PRIME. den i add ocean-free black water.
currently the filter used is just a bio-mechanical filter.

how do i ensure that the baby fries grow up into healthy fish?