This is how you want your sweater to look when you go to wear it.
So most people put the hanger in here, like a shirt.
But since the sweater is heavy and stretchy, it can end up putting those little bumps in the shoulder.
To fix that, start by folding your sweater in half.
Place the hanger here, with the metal hook in the arm pit.
Fold the waist over one side of the hanger.
And fold the sleeves over the other side.
This is your finished product. The weight is broadly distributed so you won't overly stretch and ruin your sweater.