When to do it: The night time is the right time for squid, as this is their prime feeding time. It's better at high tide and during the full moon, but as long as you're going at night you're likely to catch something.
Where to do it: Pick your favorite pier. Well-lit is best, like the Des Moines Marina pier, as the squid are attracted to light. For an even bigger impact, you can set up a shop light to shine directly onto the water where you drop your jig, as this will attract even more squid.
How to do it: Once you've found your well-lit spot (or made a well-lit spot for yourself), set up your bucket and pole and get to squidding. Set up your pole with a squid jig, using 1-3 jigs per line. More advanced anglers use multiple jigs, but one is best for a beginner. Charge up your jigs using your flashlight (or the flashlight on your cell phone). Because the jigs glow in the dark, they need to be hit with bright light for a few seconds to make sure they glow underwater. Once you're set up, there's no need to cast, just drop the lure down. Take the rod and "jig" it up then lower it slowly, making the lure look more like a real shrimp. When you pull up and feel weight on the line and see the pole bending, that means you've got a squid latched on! Reel it in and collect your catch. Unlike most fishing, you don't need specialized tools to remove the hook: just turn the jig upside down over your bucket, and the squid will slide right off into the bucket...though probably not without inking you first.
Tips and Tricks: You won't need a net, as these squid are fairly small and slide directly off the jig into your bucket. There will be a lot of dead time, much like with other fishing. You will sometimes see a school of squid on the water and that's when you really want to actively be squidding. It's a waiting game but when those schools come you'll catch a bunch one right after the other, sort of feast or famine.
Jig deep but not touching sea floor, as you're more likely to get your line entangled with seaweed and need to cut it, which means leaving behind trash that can affect wildlife. You might reel in some seaweed or friendly crabs or starfish, but just toss them back in. Any crabs you catch are unlikely to be large enough to be a legal catch, and crab are out of season during the winter anyhow.
And that's all there is to it! Don't be afraid to talk to any other anglers you see on the pier, and may you fill up your catch bucket quickly!