Bind offs, also known as cast offs, are useful tools in knitting because they help you keep one area of your project in place while you work on another section. Bind offs on a circular needle work basically in the same way that bind offs work with straight needles.
To do a bind off to remove your cast ons, simply move the needle over the thread. To learn how to do this super useful knitting trick, check out this knitting video. Whether you're a beginning knitter or advanced, this is an excellent method to learn.