Looks like NashobaTek beat me to it! But yeah the article's a good way to do it! I'd also recommend checking out April Kirkendoll's "How to Raise and Train your Peppermint Shrimp". It's a chill read!
Also, a lot of the information I'm about to type is similar/duplicate to that found in the article/info that was already shared, but figured it might be useful in case somebody stumbles across this thread in the future:
Larval peppermints eating algae: Sorry, they hatch out carnivores, and ready to eat newly hatched baby brine shrimp (you can buy this online! I like BrineShrimpDirect for their large cans). If larval peppermints ate benthic algae, then we'd have a lot less problems in the hobby, and a lot more adult peppermints. That being said, it's always beneficial to have live microalgae in the growout container, since it helps sop up a lot of the excess nitrogen and increases oxygen content, etc. Adding a rock to the growout tank is a good idea, but keep in mind that these are fragile, pelagic shrimp. They don't like bumping into things until after they metamorphose.
Light-attraction: In science, we call it phototaxis

, sunflowers are really good examples of it in non-animals. Larval peppermint shrimp aren't the strongest swimmers, but in the right conditions (low-non-existent flow), they'll be able to get to the light, which makes them easier to collect! That being said, turning the lights off on the tank for a day or two isn't going to affect survivability, since you have around 8-12 hours or so in order to collect the larvae before the currents in the tank kill them, they get eaten, or something happens.
Flow: Larval peppermint shrimp are incredibly weak. Like, super weak. They can't fight current for quite a while, so turning off the pump on hatch night will help in getting the larvae to where they need to be (which is another water container!)
Feedback on the setup tank: I like it, if you take out the sand and the blue cave thing! Just toss microbacter7 in the tank, and make sure the heater's indicator light is covered (phototactic larvae!). Depending on the tank's length and total gallonage, you could start off with the tank half full, so you can increase brine shrimp density without having to hatch out more brine shrimp! A bonus is that you can also help dilute waste in the tank by adding water in, versus taking water out and adding more water back in. Oh, and it should be a tank for only peppermint shrimp, no clownfish, no fish, literally nothing except for the peppermint shrimp.