(RS) K2, sl1, psso, K to last 4 stitches, K2tog, K2
(WS)P2, P2tog, P to last 4 stitches, P2tog, tbl, P2
Last two rows set the decreases
Working decreases as set, dec 1 stitch at each end of next 1 row, then on every following alternate row until 45 stitches remain.
They have showed you how to work the decreases depending on whether or not you are on a RS or WS row. Continue to knit in stockinettte and work decreases as you are told (next row and then every other row) until 45 sts remain.