I actually did this last week as a nice treat for my fish!! I got a clear plastic container full of water (or a pop bottle as some people have suggested already), and added 2 teaspoons of table salt!!! Put in a teaspoon of brine shrimp eggs and pump some air in it for 24 hours or so. after about 24 hours, take the air pump out and let the water settle a few min. Wrap the conainer with a few sheets of paper (or if it is a pop bottle, it already has the plastic around it).
Lay a flashlight down shining into it for 20 min or so. When you look at it after the 20 min, you will see the little brine shrimp vibrating in the light. Brine shrimp are pink, eggs are brown/black.
Take a baster (I went to the dollar store and got a cheap one) and suck up all the brine shrimp at the light.
Dump them into a batch of freshwater (dechlorinated) in another container or another pop bottle, to "rinse" them off and to dilute the water, so you dont add so much salt to your freshwater tank (if you have a fresh water tank).
do the paper around the container if you need to again, and shine the light in at the bottom of the container.
After a few min, suck up the brine shrimp again, and dump them into your tank.
THEY ARE REALLY SMALL but the fish can see them! I watched the fish swmming all over biting "nothing". That was really the brine shrimp.
You can feed them and grow them a bit more, but maybe you should not use table salt for that, maybe proper salt is better
Good luck!