how do you know when to use a direct or an indirect object pronoun?

Direct object pronouns: me, te, le, la, nous, vous, les me, you, him, her, us, you (pl), themIndirect object pronouns: me, te, lui, nous, vous, leur to me, to you, to him/her, to us, to you (pl), to themObject pronouns replace the noun in a sentencee.g. I see the book= je vois le livreWe must replace the noun le livre. As it is masculine we use the masculine object pronoun "le".Therefore: I see it (the book)= je le voisThis is replaced by a direct object as there is no preposition before the nounAn example of an indirect object is:I am calling John with my mobile= Je téléphone à Jean avec mon mobileBefore our object in this case we have the preposition à so we must use an indirect object pronoun, in this case lui.I am calling him with my mobile= Je lui téléphone avec mon mobileIndirect objects can be thought of as though you have to take a stop in the sentence before you arrive at the subject whereas with direct objects you arrive straight there without stopping in between subject and object.