How to teach toddler (2.5yrs) to stop hitting newborn baby brother!

Je

My 2.5 year old son has started hitting his newborn baby brother lately. The first two weeks baby was home with us, my toddler acted loving & did not hit him. But recently he started hitting the baby & acting up in other ways too.

What do I do to fix this?

How do I create a healthy environment for both of them at home, where no one feels hurt or left out?

Any & all advice welcome 🙏🏼