This Mood is similar to the Conditional Perfect:
I would have eaten: J’aurais mangé.
But remember, we also use the verb to be as an auxiliary, so, for example:
He would have gone: il serait allé… (don’t forget the agreement with the past participle: elle était allée)
So you just need to know the conditional of the verbs avoir and être!
We use the Passé Conditionnel with:
1. If sentences
2. Regret or criticism
3. Unverified Facts
I would have come if I had known it: je serais venu si j’avais su.
We would have eaten it if it had been good: Nous aurions mangé si cela avait été bon.
In your place, I would have talked to him: Perso, je lui aurais parlé.
I would have liked to go on holiday: J’aurais aimé aller en vacances.
Apparently, he had lied to the court: Il aurait menti au tribunal.
All the passengers have been killed: tous les passagers seraient morts.
He could have gone: Il aurait pu y aller