Help with earflap hat

I am not understanding this patten instructions.
Using circular ndl, if desired, and MC (right where you left
off on second earflap), knit across sts of 2nd earflap, then,
using backward loop method, loosely CO 20 (22, 24, 28,
30, 34) front sts, knit across sts of 1st earflap, loosely CO
16 (18, 20, 24, 26, 30) back sts, PM and join in rnd, being
careful not to twist sts. [56 (64, 72, 80, 88, 96) sts]

What I don’t understand is CO front sts, and CO back sts.
This is a pattern for a baby hat on Raverly called “Cozy”. I have made my ear flaps but don’t understand how to CO these sts.

Any help would be appreciated.

Use the knit or cable cast on here. Both are demonstrated on the Free Videos tab at the top of the page, under Cast On. You’ll knit across the sts of earflap 2, switch the needles in your hands so that the needle with the earflap sts is in your left hand and cast on the sts for your size, then switch the needles back and knit the sts of earflap 1. Repeat the cast on for the correct number of sts for the back of the hat and then join in a circle.