First of all, you have to be wary of the cysts you buy. If they are not kept refrigerated, the shelf life is not very long. The cysts should be kept at 40F or a little lower, and moisture free.
Too many packets in stores are stale and hatchout can vary from poor to nil.
As for grow out, depending on what quantities you wish to cultivate, it can be easy, for low density growth, or labour intensive for high density culturing.
Low density can be as easy as putting a few hatched nauplii in a container with a little green water, and leaving them for about 3 to 4 weeks.
For high density it requires aeration and water changes meaning, work.
If you can buy live adults locally it would be the easiest.
I have to grow mine because I haven't found a Canadian source for live adult brine shrimp.
RAISING BRINE SHRIMP TO ADULT