[verb] + me / you / him / her / it / us / them
[preposition] + me / you / him / her / it / us / them
An object pronoun is the person or thing that receives the action. It comes after the verb. The subject pronoun comes before the verb.
Each subject pronoun has an object form. You and it don't change.
After a preposition (with, for, to, at, from, about), always use the object form.
It and them are for things too.
When the pronoun stands alone, or comes after be, use the object form.