7.6.2 the position of the pronouns if there is an infinitive
As we already mentioned before (7.1.1 position of the personal pronouns) the personal pronouns and the reflexive pronouns can be added to infinitive, but in this case they are combined. Me, lo, te, la, ce, lo, ve, li etc. becomes melo, tela, celo, veli, etc. The finale e of the infinitive (comprare, finire, vendere) is omited in this case.
I can give it to you. Ich kann es dir geben. Posso dartelo.
as well: Te lo posso dare.
I must go there. ch muss dahin gehen. Devo andarci.
as well: Ci devo andare.
You can' t allow yourself that. Non puoi permettertelo.
as well: Non te lo puoi permettere.
You must them for yourself. Dovete comprarveli.
as well: Ve li dovete comprare.
We have to bring it there. Dobbiamo portarcelo.
as well: Ce lo dobbiamo portare.
We want to give her some of it. Vogliamo dargliene.
as well: Gliene vogliamo dare.
In some cases, for example it the infinitive is the subject oft the sentence, the pronouns must, in other words there is no choice, be added to the infinitive.