You didn't research this before hand?
At this point you don't have time to culture foods so your going to have to use an egg yolk. You can look through posts on this forum for how best use it.
You need to look up how to hatch baby brine shrimp and go ahead and order the eggs. You can feed BBS after 2 weeks but you'll need to feed the egg yolk the first two.
Fry do much better with live foods and I don't know how well they are going to do with the egg yolk. Many fry are not going to eat unless they see something moving that sparks their predatory instinct.