Knit to where your pattern tells you to wrap & turn.
Bring the working yarn to the opposite side of your work, so if you've just done a knit stitch bring your yarn to the front as if you were about to purl and if you've just done a purl stitch bring your yarn to the back as if you were about to knit.
Slip the next stitch purlwise.
Return the working yarn to its original position, so for example if you brought it to the front of your work in step two return it to the back.
Slip the stitch which was slipped in step three back to the left needle.
There should now be a wrap around the stitch you just slipped to the left needle. You may wish to add a stitch marker to this wrap to make it easier to find when you later need to resolve the wrapped stitches (this can also be called picking up wraps).
Turn you work and knit to where your pattern tells you to wrap & turn again, then repeat steps two to six.
After completing as many wraps and turns as your pattern calls for, your pattern may then tell you to knit across your row resolving (or picking up) the wrapped stitches. To resolve a wrapped stitch on the right side of stockinette stitch, pick up the front of the wrap with the left needle from back to front (you may need to use the right needle to lift up the wrap and make this easier). Then knit the wrap together with the following stitch.
To resolve a wrapped stitch on the wrong side of stockinette stitch, pick up the back of the wrap with the left needle from front to back (you may need to use the right needle to lift up the wrap and make this easier). Then purl the wrap together with the following stitch.