What do I do with fry?

I got three female guppies from an all female guppy tank about a week ago. Pretty sure 2/3, if not all, are pregnant. I specifically got all female because I didn’t want to deal with fry. I should have expected them to be pregnant looking back. Now I’m left with not knowing what to do with the guppy fry. The tank is not big enough for anymore fish in my opinion, so I don’t plan on keeping them. What do i do to prepare for them to give birth? And what do I do after?