Correction: what is the difference

To decide is to make a decision e.g. shall I go to the cinema? Yes I will go to the cinema. You have decided.

To arrange is to organise or plan something e.g. arrange to go to the cinema with friends. Make arrangements (plans) to go to the cinema with friends.

To arrange also means to place things in a proper or desired order e.g. books on a shelf or flowers in a vase.

I hope that helps.

Thank you karen.