While the hook sweep is most commonly played from butterfly guard there are variations for use from closed and open guard as well.
Steve Campbell first explains how to do a classic hook sweep. If your opponent manages to post an arm stopping the sweep. Then Steve teaches how to transition smoothly into a straight armbar. Should your opponent be aware of the threat of the armbar and turn their hand palm up avoiding the armbar. Then Steve has a third variation that flows from the failed armbar back into a hook sweep.
Ryron and Rener Gracie explain how to do a classic hook sweep from open guard against a standing opponent. This video may have been filmed with a potato but the content is gold. This is a great basic sweep that comes up a lot for lower belts (or in a street fight apparently.)
John Danaher explains the role of each leg in a hooking sweep. The power is in the bottom leg not the lifting/hooking leg. Great solo drill and a drill with a partner where you pause at the top, forcing you to use technique and not momentum to make the sweep. Follow this and your hook sweep will get you out of guard and into top position more often than not.
John Danaher explains every detail of open guard and teaches 4 sweeps from open guard.
Watching John Danaher always shows me how much I don’t know. There’s so many fine details to each large movement. I take a sleeve grip, John takes a sleeve grip then twists the sleeve under the jacket creating a line of tension up the sleeve massively increasing the control. John ability to explain a move, why it works and all of the fine details required to make it work against a skilled opponent is unparalleled in the world of online instructional Jiu Jitsu videos.