The scarf/cowl is knitted in an eyelet rib pattern which is also used as the buttonholes for the buttons. The cowl can be buttoned up in a number of ways to make a close fitting cowl/snood or a longer draping scarf depending on whether you use 2 or 3 skeins of the yarn.

The yarn is from Knitting4 fun

I have added 3 more pictures to show the placement of the buttons at each end of the scarf/cowl.