Portuguese has approximately one squillion and three different pronouns. In English, we tend to use the same few words for all the different types of pronoun, so we often don’t even realise that there are so many different types.
We don’t have that luxury in Portuguese though, so we have to delve a bit deeper into the fascinating/irritating world of these interesting/annoying little words (delete as applicable). Using pronouns correctly is quite difficult – even the Portuguese themselves use them incorrectly sometimes, so try not to punish yourself too hard if you occasionally get your indirect objects mixed up with your prepositionals.