A few components
A grate, a ziploc storage container (or rubbermaid shoe box if you're big scale) and a way to 'float' your grate. You also need heat, but if you've got a light strip... you've got heat.
I use a 'seed sprouting lid' that fits on a mason jar. I had it laying around from when I got into alfalfa sprouts. (Came in a 3 pack and i use the one with the biggest holes for my snails now.)
Most people use plastic craft canvas. Use the kind with bigger holes. You can usually get a 'round piece' for about 50 cents. You can also get a round flat ring of stryofoam the same size as the ring for less than $1. You just glue the ring of plastic canvas to the foam with hot glue, and then float the ring inside of a storage container. The grate keep water from pooling around the eggs.
I use my 'sprouting' lid right in the container because its designed to screw onto jars it has a rather tall lip. I put about an inch of water in it, but with a floaty hatchery you can make it as deep as you want, so long as there is enough head room.
In a pinch you can use a piece of foam (cou--pink--gh) and float the eggs directly on that. The major problem when using foam directly is that water collects on the foam and forms puddles. You don't want puddles cause this drowns the embryos.