To scratch your head is to rub the scalp while puzzled. Scratch your head over the instructions.
It is one of the displacement movements people make when stuck, alongside rubbing the neck. Something that makes you scratch your head is confusing rather than annoying.
1phrasescratch your headTo rub the scalp while puzzled.
“The wiring diagram would make anybody scratch your head.”
scratch your head is a gesture.
Practised in Body Language & Gestures