This cowl couldn't be simpler. In fact, if you're looking for a project suitable for a novice knitter you could do worse than this cowl.
For this one I used three strands of lace weight (all the same yarn), one strand of sport weight and one strand of fingering all held together to produce something approximating chunky to super-chunky weight. I used 9mm (US 13) needles, because they are the biggest ones I own. My cowl came out to be 7" (18cm) wide. The exact width isn't vital as long as you're happy with the size you get, but bear in mind you want to be able to see out over it. A wider cowl can be folded in half lengthways as shown, though, for a really squooshy cowl (and if that isn't a real word it ought to be!)
The pattern goes like this:
Using 5 strands held together (as above), cast on 22 stitches.
Knit in garter stitch until work measures 20" (51cm) long.
Fold in half end-to-end with the right side innermost and sew the cast on and cast off edges together (that's the short ends).
Fold back the right way out and pull on over your head!
And that's it. Very easy. Mine used approximately 100 yards of each strand of yarn, but again, if you've got more yarn available, make a longer cowl and that gives you the chance to wrap it twice for extra insulation.
Or if you want to pretend to be a gangster, you can wear it like this!