Increases on Garn Studio pattern

[candicane]

Can someone clarify the increases on this garnstudio headband pattern?

Headband: Start at center back. Cast on 19 sts. Knit rib as follows:
Row 1 (right side): K 1 (edge st knit in garter st), * K 2, P 1 * repeat a total of 5 times – finish row with K 2 and K 1 (edge st knit in garter st).

Row 2 (wrong side): K 1 (edge st knit in garter st), * P 2, K 1 * repeat a total of 5 times – finish row with P 2 and K 1 (edge st knit in garter st).
Make all incs on right side rows.

When the piece measures 8 cm inc all P 1 to P 2 = 24 sts.
When the piece measures 14 cm inc all P 2 to P 3 = 29 sts.
When the piece measures 18 cm inc all P 3 to P 4 = 34 sts.
When the piece measures 21 cm inc all P 4 to P 5 = 39 sts.
When the piece measures 24 cm place a marker = this is the center of headband.
Now reverse shaping – measure from marker.