Infine, quando tutto sarà in ordine, ce ne andremo a casa con la sensazione di aver vissuto un giorno perfetto.

Infine translates to “finally,” “lastly,” or “in conclusion.” You use it to introduce the last point or final step in a sequence of events. It’s slightly more formal than alla fine, which often refers to the concrete “end” of something.

In Italian, after temporal conjunctions that point to a future moment—quando, appena, finché, etc.—the verb typically appears in the future tense. So here quando tutto sarà in ordine literally means “when everything will be in order.” In English we often use the present (“when everything is in order”), but Italian keeps both verbs in the future.

Because Italian uses the pronominal verb andarsene (“to go away, to leave”). In its conjugated form you need two pronouns:

• ce (apocopated form of ci) indicating “from here”
• ne indicating movement “away, off”
  So ce ne andremo = “we’ll leave from here,” which naturally implies “we’ll go home.” You could drop ce ne in very casual speech, but then you’d lose the nuance of departing that place.

• ce stands in for ci, meaning “here” or “in this context/place.”
• ne pairs with andarsene to express “to go away from” something.
  Together, ce ne emphasizes “we’ll take ourselves away from here.”

After nouns of perception or feeling (like sensazione, paura, desiderio), Italian uses di + infinitive to introduce what is perceived or felt. Because the living happened before the feeling, you need the perfect infinitive aver vissuto (“to have lived”). So sensazione di aver vissuto un giorno perfetto literally means “feeling of having lived a perfect day.”

Un indicates “one (unspecified) perfect day” among many possible days. If you said il giorno perfetto, you’d be pointing to one specific, known “perfect day.” Here the speaker just wants “a perfect day” in general.