Is he being aggressive or protective? At this young age, it is likely protective reaction due to fear of the unknown. If so, punishment will not help, and can make it worse.
Is he being forced into something he does not understand or is afraid of public failure and being mocked?
Are there sources of over-stimulation (lights, sounds, motion, smells)?
If it is fear, then your complete understanding of the situation, and carefully braking down the activities through pictures and words to explain to him the 4 w's & h (what, why, when, who, and how) and address his fears can resolve this situation (others might pop up). Often times teachers give instructions that briefly describe the "what" to do, without enough context that visual thinkers can understand.
If it is over-stimulation, address each source separately, again giving full visual and verbal explanation of what the source is and why it is not harmful so that he does not need to focus on it.