Reverse stockinette stitch just means that the purl side (bumpy side) is on the 'right' side and the knit side (v side) is on the 'wrong' side.
I'm not sure what your question is about the twist stitch. If the pattern says to do it, do it. Is it that you don't know how? There should be directions for all the stitches called for at the beginning of the pattern.