This pattern begins the back essentially with k2, p2 rib and then lace pattern #1 for 6 rows and then lace pattern #2 (st 1, 8sts of the chart, an 8st repeat which is boxed off and repeated 11 times, the 4 last sts of the chart, then k2). Finish the 36 rows of the chart. You will be starting at the bottom of the chart and working up according to the instructions.
BTW There's a correction to lace pattern #3 in this sweater
LACE PAT 3
Row 3 was misidentified as row 5; replace rows 3 and 5 with the following:
Row 3 K1, *yo, S2KP, yo, k5; rep from *, end last rep k1.
Row 5 Repeat row 1.