At my wits end with 1yr old hurting 4 yr old

[Babybirdmum]

My nearly 2 year old keeps hitting/scratching/pulling hair of my 4 year old and I don’t know what to do anymore. Saying “no” “show gentle hands” and time outs are not working. Any tips?

You need a physical barrier

So different rooms etc

What does show gentle hands mean? It’s vague.
immediately intervene with a firm no! Explain explicitly why it’s wrong.
routinely praise good behaviour so not only the inappropriate behaviour