Something about verb conjugation of 'Passe Compose'.
If I would say "I built the house" in french, it should be like "J'ai construit la maison." But if I say "I built it", it means the house, which is a feminine noum in french, should I say : "Je l'ai constuite" or "Je l'ai construit" Should or when the passe compose conjugation with 'avoir' go with the gender? (We all know if passe compose conjugation with etre, the main verb should have gender and plural go with it.)
Short answer: Je l'ai construite. Because avoir is the auxiliary and the direct object pronoun is before the verb.
Longer answer: There are additional details re: agreement. Below is a helpful link.
And if you don't already know about it, the following website is helpful to study verbs. Another option is the Bescherelle 12,000 French verbs book (which I highly recommend).
I find https://leconjugueur.lefigaro.fr/conjugaison to be one of the best online conjugators for French.
Bescherelle is also available online @ http://bescherelle.com/conjugueur.php?term=construire