Work even means to work in stockinette with no increases or decreases until your piece measures 19.5". End by working a purl row. On the next row, a knit row, bind off 4sts, place a marker and knit to the end of the row, place a marker. Turn to the purl side and work the first 3sts in stockinette. The pattern should continue with how many rows or inches to work the 3sts in stockinette. (And there must be a reason for the markers at the ends of the rows.)
Do you have a link to the pattern or a pattern name?
The book is called 100 Kniting project . But before that it says rep rows 8 through 13 until there are 46 sts then the work even in stock st until piece measures 19.5 from co edge, ending by working a purl row
It’s still the same - do the repeated rows until you have 46 sts, then work without increasing until the total lenth is 19½" and end on the purl row. On the next row, the knit one, BO 4 sts at the beg of the row, put a marker on the needle and finish the row. Then do 3 more rows.