When you're seeking after bodily pleasure of food and drink for example, this is going to prevent you from doing what you should be doing which is contemplating.

Plotinus thought that the entire world has a single soul. He also thought that each animal and plant and of course human, has an individual soul.

Sometimes clichés are true.

The forms in intellect are some kind of blueprint or model on which the physical world is based, and something needs to come along and shape the matter in accordance with that blueprint. What does that is soul.

The soul must be distinct from intellect because even at its best, what the soul does when it's thinking, is it thinks linguistically, it thinks in a temporarily extended way, so it for example, might go through the steps of an argument chain, as if you were going through a syllogism and seeing that something followed from the premises, whereas intellect simply grasps the forms.

This condition of uncertainty and unrest in the Roman Empire might explain why at Plotinus' philosophy encourages us to sort of flee from the physical world and towards the world of ideas.

Soul puts the determination or forms or images of forms, into matter.