Knitting! What does "work three rows EVEN" mean?

Yes, you continue to work in the pattern as it has been established. You will see this instruction in many patterns. If you are working in stockinette, you will continue to work in stockinette, IOW, if your next row is knit, knit it, then purl a row and knit a row. If you are knitting another combination in a different project you will go back to the first pattern row and work it to the last pattern row as far as the instructions tell you to knit. This applies to most patterns, including simple lace patterns (complex lace sometimes has full repeats of a single pattern especially in a stole, but not always), cable patterns, and, yes, crochet patterns.

Good luck with your baby cardigan, baby sweaters are a very good place for a novice knitter to learn their construction skills for larger sweaters, just as lace face cloths and dish cloths are good for beginning to learn lace work. Afghan squares of different stitch combinations and color changes are good learning tools as well to expand your abilities and repetoire.

Knitting Work

That is poorly written, if it does in fact say that. What it probably means is that you do 3 rows of purl that shows on the front of the fabric. I don't know if you are doing these flat or in the round, so can't give specifics. But you want to have the purl side showing on the outside of the fabric... so anyway you need to do it, that is right.

work three rows mean knit one row, purl one row, knit one row

working on a scarf, what does &even rnds:knit