When you are ready to use the stitches on the provisional cast on for adding an edging, or knitting in the opposite direction, or doing a three needle bind off, you need to release them from the crocheted chain.
Unpick the fastening at the end of the crocheted chain (helpful hint: tie a knot in the tail of this end so you know which is the start and which is the end of the chain when you come back to it) -- the chain should start to unravel quite easily.
Carefully place your live stitches on a knitting needle as they become exposed -- they are now ready to be worked. Make sure there are the required number of stitches on the needle -- at the edge if there is one extra or one missing, now is the time to fudge it with a surreptitious increase or decrease.
Helpful hint: place the live stuiches on a smaller needle than you will be working with -- it makes them much easier to pick up and you are less likely to lose one.