Do not be put off by the apparent length of the written directions. Remember: with any slipped stitch pattern, 2 rows of knitting make 1 row of pattern. Remember:

Knit all right side rows.
Purl all wrong side rows.
Slip all stitched purlwise, with yarn ALWAYS carried on the
RIGHT or PUBLIC side of work.
In the simplest of terms, the pattern alternates (1 row of plain knitting in one color and 1 row of slipped stitches) 2 times, then 1 row of slipped stitches and either 2 or 3 rows of plain knitting in one color.