I checked the book. That's the right title. I've got the fourth edition. It was cheap second hand on eBay. I recommend it. Author is Emily Spinelli. In my copy, the info you're after is in chapter 38.
I can't really top what WaterBowlSlime said, but I'll give you some of what the book says so you see what I mean when I say it's helpful (I'm not going to be exhaustive, though).
Pronouns used as direct and indirect objects are called object pronouns.
Paul saw her. Paul saw whom? Answer: Her. Her is the object of the verb saw. …
In English Most object pronouns are different from subject pronouns, but the same pronouns are used as direct objects and indirect objects.
Subject pronouns are: I, you, he, she, it, we, you, they.
Object pronouns are: me, you, him, her, it, us, you, them.
For example:
She saw me.
'Me' is the direct object and is a pronoun = direct object pronoun.
But 'me' can also be an indirect object pronoun. For example:
He lent me the car.
'Me' is the indirect object and is a pronoun = indirect object pronoun.
The chapter then explains what is different and similar about Spanish (in)direct object pronouns.
When 'you' would be 'tú' (informal singular) or 'vosotros' (informal plural), the direct object pronoun to use is 'te' (for tú) or 'os' (for 'vosotros). 'Me' stays as 'me'. 'Him' becomes 'lo' (not él). 'Her' becomes 'la' (not ella). 'Us' becomes 'nos' (not nosotros/as). Examples:
John sees me. Juan me ve.
John sees you. Juan te ve (informal, singular [tú form]). Or: Juan os ve (informal, plural [vosotros form]).
Do you seen John? Yes, I see him. ¿Ves a Juan? Sí, lo veo.
Do you see Mary? Yes, I see her. ¿Ves a Mary? Sí, la veo.
John sees us. Juan nos ve.
The direct object pronoun is slightly different for 'it', 'them' (and these change by gender), and for 'you' (when 'you' is polite and singular or plural). So 'it' and 'you' (formal singluar, 'usted') becomes either 'lo' (masculine) or 'la' (feminine). So 'them' and 'you' (formal plural, 'ustedes') becomes either 'los' (masculine) or 'las' (feminine). The gender, here, depends on the noun that they are replacing (called the 'antecedent'. So e.g. the antecedent for 'las' could be 'las chicas' ('the girls'). Examples for 'it'/'them':
Do you see the book? Yes, I see it. ¿Ves el Libro? Sí, lo veo.
Do you see the table? Yes, I see it. ¿Ves la mesa? Sí, la veo.
Do you see the cars? Yes, I see them. ¿Ves los coches? Sí, los veo.
Do you see the girls? Yes, I see them. ¿Ves las chicas? Sí, las veo.
Examples for 'you' when 'usted' or 'ustedes' would be needed:
Whom does John see? He sees you (polite, speaking to a singular male). ¿A quién ve Juan? Juan lo ve.
Whom does John see? He sees you (polite, speaking to a singular female). ¿A quién ve Juan? Juan la ve.
Whom does John see? He sees you (polite, speaking to a male group or mixed group). ¿A quién ve Juan? Juan los ve.
Whom does John see? He sees you (polite, speaking to a female group). ¿A quién ve Juan? Juan las ve.
You may notice that the book separates 'him' and 'her' from 'it', 'you', 'them', even though they seem to have the same pattern ('lo'/'la'). Don't ask. I have no idea why. I'd have kept them together, but maybe I'm missing something.
We can see from these examples that Spanish has more direct object pronouns than English. Where we might use 'you' in English, in Spanish we might need: 'te', 'os', 'lo', 'la', 'los', or 'las'. The last three are trickiest because we have to remember that the 'usted' 'you' and 'ustedes' 'you' often take the same for as 'they'/'it'/'them' because when we use 'usted' and 'ustedes', we're talking about the other person in the third person. Kind of like in historical dramas when e.g. a priest calls the king (sat in front of them) 'his majesty' rather than 'you' or 'your majesty'.
The book has examples for indirect object pronouns too but it's… erm… quite painstaking to type out this kind of thing, so I'll leave it here and encourage you to find a cheap copy of the book or find a PDF (the 3rd and 4th editions seem to be available on the high seas – in the third edition, I would hazard a guess that the relevant chapter is 39). I'll finish by saying that 'le' is the indirect object used when you would say 'him, her, you [usted form]', and 'les' is the indirect object used when you would say 'them, you [ustedes form]'. And 'indirect objects do not distinguish between gender'.
Hopefully this makes sense. I think it's easier in practice than in theory, once you're aware of the broad idea.