Welcome to KH!! No such thing as a dumb question either!!
You will need to get a circular needle in the same size as your 14" needle (say you are knitting with a size 8 then you will want a circ in size 8)...they have different sizes of cables for the most part I find a 32" to be comfy for a shawl/wrap...sometimes I work on a 24" with no problem too
Since you can knit back and forth on circs without joining and also in the round you may want to start buying only circs...or look into an interchangeable set...
