The French way of saying leave

French uses several words for leave. It is very confusing for me. 

The French words are laisser, partir, se partir, conge, quitter etc.

Please tell me how to select the correct French word for leave. This is a tall order for me.

You can leave home.

I must leave home immediately.

You are leaving on holiday.

He left the country last year.

He left our company nearly a year ago.

He quit his job.

I left something at my brother's house. ( Here I have forgotten an item.)

In English, we say please leave me alone. 

Instead of don't disturb me, we can use the above.

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Pourquoi ne prenez-vous pas quelques jours de congé? 
Why don't you take a few days leave?

Elle est en congé de maternité.  
She is on maternity leave.
( I am not sure about my French sentences.)