There are various ways to tie catfish rigs. I used to use helicopter rigs because they are absurdly easy to tie and require only two things—a sinker and a hook. I first learned how to do one from this video.
But, the more I fished the Potomac River and Tidal Basin, the more I grew annoyed with helicopter rigs because they tend to get twisted—the hook portion of the line gets wrapped around the sinker line due to the water current. Don’t get me simple wrong—helicopter rigs are a fine way to start, and they can be used if you are short on gear (like if you’re in a boat and lose a nice rig and have insufficient materials to re-rig.). And helicopter rigs can work great if you buy some additional materials that keep the lines from twisting around each other. (See this photo. And, yes, some folks put the weight above the hook and others below it.)
This is sometimes called a “zero rig“—but I refer to it as a simple catfish rig because is shows simple, clean profile—a single line with the hook at the end and a single sinker. here’s a 4-minute video I made showing how to make this rig. Below the video you will see links that will enable you to buy the various components (circle hook, flat sinkers, Lindy plastic beads, and 30- or 40-pound monofilament line).
I advise tying 3 or more of these rigs before you go to fish. Then clip them on to a swivel clip that’s attached to your reel line. This enables you to bait up quickly, and to replace a rig if one gets lost (due to a snag) or damaged. Enjoy!