You will eventually need to pick up stitches from waste yarn or stitch holder if you have previously been instructed to place your stitches on a stitch holder or waste yarn. Generaly stitches are returned to needles, or picked up, prior to the next instruction. Below are several scenarios for picking up stitches from waste yarn or a stitch holder. Waste yarn is my personal preference, so it is what I expect to encounter. You may have put your stitches on a stitch holder, in which case you should substitute stitch holder for waste yarn.
Pick Up Stitches from Waste Yarn
This may also be stated as return stitches on stitch holder or waste yarn to needles. Working from right to left, put the needle into stitches purl wise. If working in the opposite direction, the needle goes into stitches knit wise.
There are multiple other ways to approach picking up these stitches from waste yarn or stitch holder, and most of these are used in specialized applications.
PU – pick up
WY – waste yarn
k2tog – knit two stitches together
p2tog – purl two stitches together
Pick up stitches from waste yarn and knit
Pick up the top of the stitch on WY onto the left needle then knit it.
Pick up stitches from waste yarn and k2tog
Pick up the top of the stitch on WY onto the left needle and k2tog with the next stitch on the left needle.
Pick up stitches from waste yarn and p2tog
Pick up the top of the stitch on WY onto the left needle and p2tog with the next stitch on the left needle.
Pick up marked stitches from waste yarn
Insert the needle into the marked stitches on WY to return them to the working needle, taking care to orient all the stitches in the same direction.