Bonjour Anaïs,

The verb conjugation depends on the subject grammatical person. 

What is a subject grammatical person?

There are three singular and three plural.

Singular: Je, Tu, Il, Elle (Il, Elle are singular male and female singular gender)

Plural: Nous, Vous, Ils, Elles (As above, Ils and Elles plural gender)

On    May be singular or plural depending on the context.

Vous can be singular polite or plural but depending on the context.

So to answer your query -- the verb conjugation strictly relates to the Grammatical Person.

The object pronoun of the verb depends upon it being direct to the verb or indirect to the verb.

https://www.lawlessfrench.com/grammar/verb-conjugation/

I hope this and the above link will help.

Bonne continuation 

Jim