What does this mean?
*(knit 1, purl 1, knit 1) all into next st, purl 3 together; repeat from * to last 12 sts:??

Knit into the stitch, but don’t slide it off. Bring the yarn forward between the two needles and purl into the same stitch, and don’t slide it off. Bring the yarn back between the two needles and knit into the same stitch. Then slide it off. You’ll have 3 stitches instead of one.

Then you purl 3 stitches together as one, and repeat these two steps across the row.

i think it means to knit one, then purl one, then knit one all into the same stitch; then purl the next three stitches together (instead of putting the right needle into the next one stitch to purl, you put it through the next three). repeat all that until you have 12 stitches left. there should be instructions for those last 12 stitches.
i’ve never purled more than one stitch at a time, but i’ve heard it’s not fun. good luck! :hug:

just out of curiosity, what are you knitting?

thanks! I am knitting an afghan, and while I know how to knit and purl, I haven’t read a pattern for about 30 years!

sounds like trinity stitch, that’s a pretty stitch (but very time consuming)
yes, It’s a little bit like a bar increase and the advice given so far was perfect

knit the stitch, dont slip off of needle, bring yarn between two needles to the front, purl stitch, dont slip off needle, bring yarn between the two needles to the back, knit the stitch, slip off of needle
with yarn in front, insert the needle into the next three stitches and purl them together