Knitting in the round makes the structure of your stitches a little different from if you were knitting them flat. So in order to create garter stitch fabric in the round, you would knit alternating knit and purl rows. To create stockinette fabric, you would knit every stitch on every row.

Additionally, if you are converting a lace chart that is worked flat to knitting in the round, the wrong side row that is usually purled across would simply be knit. So, you would work one complete row of the lace chart followed by a knit row, then back to the lace chart and so on.